[Previous reference file]
Property. A string beginning with a hash mark (#) that
specifies an anchor name in the URL.
1. links[index].hash
2. location.hash
3. areaName.hash
index is an integer representing a Link object
or the name of a Link object as specified by the NAME attribute.
areaName is the value of the NAME attribute of an
Area object.
Area object (see Link
object), Link object,
location object
-
-
Navigator 2.0
-
Navigator 3.0: property of Area
Yes
The hash property specifies a portion of the URL.
This property applies to http URLs only.
You can set the hash property at any time, although
it is safer to set the href property to change a location. If the
hash that you specify cannot be found in the current location, you will get
an error.
Setting the hash property navigates to the named
anchor without reloading the document. This differs from the way a document
is loaded when other location properties are set (see
"How documents are loaded when location is
set").
In event handlers, you must specify
window.location.hash instead of simply using
location.hash. Due to the scoping of static objects in JavaScript,
a call to location without specifying an object name is equivalent
to document.location, which is a synonym for
document.URL.
See
RFC
1738 for complete information about the hash.
See the examples for the Anchor
object and the href property.
host,
hostname,
href,
pathname,
port,
protocol,
search properties
Property. A string specifying the height of an image in
pixels.
imageName.height
imageName is either the name of an Image object
or an element in the images array.
Image
Navigator 3.0
No
The height property reflects the HEIGHT attribute
of the <IMG> tag. For images created with the Image() constructor,
the value of the height property is the actual, not the displayed,
height of the image.
height is a read-only property.
The following function displays the values of an image's
height, width, hspace, and vspace properties.
function showImageSize(theImage) {
alert('height=' + theImage.height+
'; width=' + theImage.width +
'; hspace=' + theImage.hspace +
'; vspace=' + theImage.vspace)
}
border,
hspace,
vspace, width
properties
Object. A Text object that is suppressed from form
display on an HTML form. A Hidden object is used for passing name/value
pairs when a form submits.
To define a Hidden object, use standard HTML
syntax:
<INPUT
TYPE="hidden"
NAME="hiddenName"
[VALUE="textValue"]>
NAME="hiddenName" specifies the name of the
Hidden object. You can access this value using the name property,
and you can use this name when indexing the elements array.
VALUE="textValue" specifies the initial value
of the Hidden object.
To use a Hidden object's properties:
1. hiddenName.propertyName
2. formName.elements[index].propertyName
hiddenName is the value of the NAME attribute of
a Hidden object.
formName is either the value of the NAME attribute
of a Form object or an element in the forms array.
index is an integer representing a Hidden
object on a form or the name of a Hidden object as specified by the
NAME attribute.
propertyName is one of the properties listed below.
Form object
-
-
Navigator 2.0
-
Navigator 3.0: added type property
A Hidden object is a form element and must be defined
within a <FORM> tag.
A Hidden object cannot be seen or modified by a user,
but you can programmatically change the value of the object by changing its
value property. You can use Hidden objects for client/server
communication.
The Hidden object has the following properties:
None.
The following example uses a Hidden object to store
the value of the last object the user clicked. The form contains a "Display
hidden value" button that the user can click to display the value of the
Hidden object in an Alert dialog box.
<HTML>
<HEAD>
<TITLE>Hidden object example</TITLE>
</HEAD>
<BODY>
<B>Click some of these objects, then click the "Display value" button
<BR>to see the value of the last object clicked.</B>
<FORM NAME="form1">
<INPUT TYPE="hidden" NAME="hiddenObject" VALUE="None">
<P>
<INPUT TYPE="button" VALUE="Click me" NAME="button1"
onClick="document.form1.hiddenObject.value=this.value">
<P>
<INPUT TYPE="radio" NAME="musicChoice" VALUE="soul-and-r&b"
onClick="document.form1.hiddenObject.value=this.value"> Soul and R&B
<INPUT TYPE="radio" NAME="musicChoice" VALUE="jazz"
onClick="document.form1.hiddenObject.value=this.value"> Jazz
<INPUT TYPE="radio" NAME="musicChoice" VALUE="classical"
onClick="document.form1.hiddenObject.value=this.value"> Classical
<P>
<SELECT NAME="music_type_single"
onFocus="document.form1.hiddenObject.value=this.options[this.selectedIndex].text">
<OPTION SELECTED> Red <OPTION> Orange <OPTION> Yellow
</SELECT>
<P><INPUT TYPE="button" VALUE="Display hidden value" NAME="button2"
onClick="alert('Last object clicked: ' + document.form1.hiddenObject.value)">
</FORM>
</BODY>
</HTML>
cookie property
Property. An array reflecting all the history entries in
a window in source order. See the history
object for information.
No
Object. Contains information on the URLs that the client
has visited within a window. This information is stored in a history list
and is accessible through the Navigator Go menu.
To use a history object:
1. history.propertyName
2. history.methodName(parameters)
3. [windowReference.]history[index]
propertyName is one of the properties listed below.
methodName is one of the methods listed below.
windowReference is a valid way of referring to a
window, as described in the window
object.
index is an integer representing an entry in the
history list.
window object
The history object is a linked list of URLs the
user has visited, as shown in the Navigator Go menu.
To change a window's current URL without generating a history
entry, you can use the replace method. This replaces the current page
with a new one without generating a history entry. See the
replace method.
You can reference the historyentries by using the
history array. This array contains an entry for each history entry
in source order; each array entry is a string containing a URL. For example,
if the history list contains three named entries, these entries are reflected
as history[0], history[1], and
history[2].
To use the history array:
1. history[index]
2. history.length
index is an integer representing an entry in the
history list.
To obtain the number of entries in the history list, use
the length property: history.length.
Elements in the history array are read-only. For
example, the statement history[0]="http://home.netscape.com"
has no effect.
If you access the history array without specifying
an array element, Navigator returns a string of HTML which displays a table
of URLs, each of which is a hyperlink.
The history object has the following properties:
The history array has the following properties:
The History object has the following methods:
None.
Example 1. The following example goes to the URL
the user visited three clicks ago in the current window.
history.go(-3)
Example 2. You can use the history object
with a specific window or frame. The following example causes window2
to go back one item in its window (or session) history:
window2.history.back()
Example 3. The following example causes the second
frame in a frameset to go back one item:
parent.frames[1].history.back()
Example 4. The following example causes the frame
named frame1 in a frameset to go back one item:
parent.frame1.history.back()
Example 5. The following example causes the frame
named frame2 in window2 to go back one item:
window2.frame2.history.back()
Example 6. The following code determines whether
the first entry in the history array contains the string "NETSCAPE".
If it does, the function myFunction is called.
if (history[0].indexOf("NETSCAPE") != -1) {
myFunction(history[0])
}
Example 7. The following example displays the entire
history list:
document.writeln("<B>history is</B> " + history)
This code displays output similar to the following:
history is
Welcome to Netscape http://home.netscape.com/
Sun Microsystems http://www.sun.com/
SlugVideo at the Dream Inn http://sapphire.cse.ucsc.edu/SlugVideo/dream-inn.html
Bad Dog Chronicles http://www.supernet.net/~dugbrown/
location object,
replace method
Property. A string specifying the server name, subdomain,
and domain name.
1. links[index].host
2. location.host
3. areaName.host
index is an integer representing a Link object
or the name of a Link object as specified by the NAME attribute.
areaName is the value of the NAME attribute of an
Area object.
Area object (see Link object),
Link object,
location object
-
-
Navigator 2.0
-
Navigator 3.0: property of Area
Yes
The host property specifies a portion of a URL. The
host property is a substring of the hostname property. The
hostname property is the concatenation of the host and
port properties, separated by a colon. When the port property
is null, the host property is the same as the hostname
property.
You can set the host property at any time, although
it is safer to set the href property to change a location. If the
host that you specify cannot be found in the current location, you will get
an error.
In event handlers, you must specify
window.location.host instead of simply using
location.host. Due to the scoping of static objects in JavaScript,
a call to location without specifying an object name is equivalent
to document.location, which is a synonym for
document.URL.
See Section 3.1 of
RFC
1738 for complete information about the hostname and port.
See the examples for the
href property.
hash,
hostname,
href,
pathname,
port,
protocol,
search properties
Property. A string containing the full hostname of the server,
including the server name, subdomain, domain, and port number.
1. links[index].hostname
2. location.hostname
3. areaName.hostname
index is an integer representing a Link object
or the name of a Link object as specified by the NAME attribute.
areaName is the value of the NAME attribute of an
Area object.
Area object (see Link object),
Link object,
location object
-
-
Navigator 2.0
-
Navigator 3.0: property of Area
Yes
The hostname property specifies a portion of a URL.
The hostname property is the concatenation of the host and
port properties, separated by a colon. When the port property
is 80 (the default), the host property is the same as the
hostname property.
You can set the hostname property at any time, although
it is safer to set the href property to change a location. If the
hostname that you specify cannot be found in the current location, you will
get an error.
In event handlers, you must specify
window.location.hostname instead of simply using
location.hostname. Due to the scoping of static objects in
JavaScript, a call to location without specifying an object
name is equivalent to document.location, which is a synonym
for document.URL.
See Section 3.1 of
RFC
1738 for complete information about the hostname.
See the examples for the
href property.
hash,
host, href,
pathname,
port,
protocol,
search properties
Property. A string specifying the entire URL.
1. links[index].href
2. location.href
3. areaName.href
index is an integer representing a Link object
or the name of a Link object as specified by the NAME attribute.
areaName is the value of the NAME attribute of an
Area object.
Area object (see Link object),
Link object,
location object
-
-
Navigator 2.0
-
Navigator 3.0: property of Area
Yes
The href property specifies the entire URL. Other
location object properties are substrings of the href
property.
You can set the href property at any time.
Omitting a property name from the location object
is equivalent to specifying location.href. For example, the
following two statements are equivalent and set the URL of the current window
to the Netscape home page:
window.location.href="http://home.netscape.com/"
window.location="http://home.netscape.com/"
In event handlers, you must specify
window.location.href instead of simply using
location.href. Due to the scoping of static objects in JavaScript,
a call to location without specifying an object name is equivalent
to document.location, which is a synonym for
document.URL.
See
RFC
1738 for complete information about the URL.
In the following example, the window.open statement
creates a window called newWindow and loads the specified URL into
it. The document.write statements display all the properties
of newWindow.location in a window called msgWindow.
newWindow=window.open
("http://home.netscape.com/comprod/products/navigator/
version_2.0/script/script_info/objects.html#checkbox_object")
msgWindow.document.write("newWindow.location.href = " +
newWindow.location.href + "<P>")
msgWindow.document.write("newWindow.location.protocol = " +
newWindow.location.protocol + "<P>")
msgWindow.document.write("newWindow.location.host = " +
newWindow.location.host + "<P>")
msgWindow.document.write("newWindow.location.hostName = " +
newWindow.location.hostName + "<P>")
msgWindow.document.write("newWindow.location.port = " +
newWindow.location.port + "<P>")
msgWindow.document.write("newWindow.location.pathname = " +
newWindow.location.pathname + "<P>")
msgWindow.document.write("newWindow.location.hash = " +
newWindow.location.hash + "<P>")
msgWindow.document.write("newWindow.location.search = " +
newWindow.location.search + "<P>")
msgWindow.document.close()
The previous example displays output such as the
following:
newWindow.location.href =
http://home.netscape.com/comprod/products/navigator/
version_2.0/script/script_info/objects.html#checkbox_object
newWindow.location.protocol = http:
newWindow.location.host = home.netscape.com
newWindow.location.hostName = home.netscape.com
newWindow.location.port =
newWindow.location.pathname =
/comprod/products/navigator/version_2.0/script/
script_info/objects.html
newWindow.location.hash = #checkbox_object
newWindow.location.search =
hash,
host,
hostname,
pathname,
port,
protocol,
search properties
Property. A string specifying a margin in pixels between
the left and right edges of an image and the surrounding text.
imageName.hspace
imageName is either the name of an Image object
or an element in the images array.
Image
Navigator 3.0
No
The hspace property reflects the HSPACE attribute
of the <IMG> tag. For images created with the Image() constructor,
the value of the hspace property is 0.
hspace is a read-only property.
See the examples for the
height property.
border,
height,
vspace, width
properties
Object. An image on an HTML form.
To define an image, use standard HTML syntax with the addition
of JavaScript event handlers:
<IMG
[NAME="imageName"]
SRC="Location"
[LOWSRC="Location"]
[HEIGHT="Pixels"|"Value"%]
[WIDTH="Pixels"|"Value"%]
[HSPACE="Pixels"]
[VSPACE="Pixels"]
[BORDER="Pixels"]
[ALIGN="left"|"right"|
"top"|"absmiddle"|"absbottom"|
"texttop"|"middle"|"baseline"|"bottom"]
[ISMAP]
[USEMAP="#MapName"]
[onAbort="handlerText"]
[onError="handlerText"]
[onLoad="handlerText"]>
NAME="imageName" specifies the name of the
Image object. You can access this value using the name property,
and you can use this name when indexing the images array.
SRC="Location" specifies the URL of the image to
be displayed in the document. You can access this value using the src
property.
LOWSRC="Location" specifies the URL of a low-resolution
version of the image to be displayed in the document. Navigator loads this
smaller image and then replaces it with the larger image specified by SRC.
You can access this value using the lowsrc property.
HEIGHT="Pixels"|"Value"% specifies the height of
the image either in pixels or as a percentage of the window height. If necessary,
Navigator scales the image to fit the space specified by this attribute.
You can access this value using the height property.
WIDTH="Pixels"|"Value"% specifies the width of the
image either in pixels or as a percentage of the window width. If necessary,
Navigator scales the image to fit the space specified by this attribute.
You can access this value using the width property.
HSPACE="Pixels" specifies a margin in pixels between
the left and right edges of the image and the surrounding text. This attribute
applies only to images that use "left" or "right" as the value of the ALIGN
attribute. You can access this value using the hspace property.
VSPACE="Pixels" specifies a margin in pixels between
the top and bottom edges of the image and the surrounding text. This attribute
applies only to images that use "left" or "right" as the value of the ALIGN
attribute. You can access this value using the vspace property.
BORDER="Pixels" specifies the width, in pixels, of
an image border. You can suppress the border by setting its value to 0; however,
if you suppress the border of an image that appears within an anchor, users
will not see a colored border indicating that the image is a hyperlink. You
can access this value using the border property.
ALIGN specifies the alignment of the image in relation
to the surrounding text. Images that are aligned as "left" or "right" float
into the next available space on the left or right side of the page, and
cause text to wrap around them. Other ALIGN values place the image in a line
of text and do not cause the text to wrap. If omitted, "bottom" is used.
ISMAP specifies the image as a server-side image
map.
USEMAP="#MapName" specifies the image as a client-side
image map. This attribute specifies the # symbol followed by the name of
the map. For example, USEMAP="#areamap".
To create an Image object:
imageName = new Image([width, height])
To use an Image object's properties:
1. imageName.propertyName
2. document.images[index].propertyName
3. formName.elements[index].propertyName
To define an event handler for an Image object created
with the Image() constructor:
1. imageName.onabort = handlerFunction
2. imageName.onerror = handlerFunction
3. imageName.onload = handlerFunction
imageName is either the name of a new object or a
property of an existing object. When using an Image object's properties,
imageName is the value of the NAME attribute of an Image object
or the imageName specified with the Image() constructor.
width is the image width, in pixels.
height is the image height, in pixels.
formName is either the value of the NAME attribute
of a Form object or an element in the forms array.
index, when used with the images array is
an integer representing an Image object or the name of an Image
object as specified by the NAME attribute. index, when used with the
elements array, is an integer representing an Image object
on a form.
propertyName is one of the properties listed below.
handlerFunction is the keyword null, the name of
a function, or a variable or property that contains null or a valid function
reference.
document
Navigator 3.0
The position and size of an image in a document are set
when the document is displayed in Navigator and cannot be changed using
JavaScript (the width and height properties are read-only).
You can change which image is displayed by setting the src and
lowsrc properties. (See the descriptions of
src and
lowsrc.)
You can use JavaScript to create an animation with an
Image object by repeatedly setting the src property, as shown
in Example 4 below. JavaScript animation is slower than GIF animation, because
with GIF animation the entire animation is in one file; with JavaScript
animation, each frame is in a separate file, and each file must be loaded
across the network (host contacted and data transferred).
Image objects do not have onClick, onMouseOut, and
onMouseOver event handlers. However, if you define an Area object
for the image or place the <IMG> tag within a Link object, you
can use the Area or Link object's event handlers. See the
Link object.
The primary use for an Image object created with
the Image() constructor is to load an image from the network (and decode
it) before it is actually needed for display. Then when you need to display
the image within an existing image cell, you can set the src property
of the displayed image to the same value as that used for the prefetched
image, as follows.
myImage = new Image()
myImage.src = "seaotter.gif"
...
document.images[0].src = myImage.src
The resulting image will be obtained from cache, rather
than loaded over the network, assuming that sufficient time has elapsed to
load and decode the entire image. You can use this technique to create smooth
animations, or you could display one of several images based on form input.
images array ">
You can reference the images in a document by using the
images array. This array contains an entry for each Image object
(<IMG> tag) in a document in source order (images created with the
Image() constructor are not included in the images array). For example,
if a document contains three images, these images are reflected as
document.images[0], document.images[1], and
document.images[2].
To use the images array:
1. document.images[index]
2. document.images.length
index is an integer representing an image in a document
or the name of an Image object as specified by the NAME attribute.
To obtain the number of images in a document, use the
length property: document.images.length.
Elements in the images array are read-only. For example,
the statement document.images[0]="logo.gif" has no effect.
The Image object has the following properties:
Note
The border, hspace, name, and vspace properties
are not meaningful for images created with the Image() constructor.
The images array has the following properties:
onAbort
onError
onLoad
Example 1: Create an image with the <IMG> tag.
The following code defines an image using the <IMB> tag:
<IMG NAME="aircraft" SRC="f15e.gif" ALIGN="left" VSPACE="10">
The following code refers to the image:
document.aircraft.src='f15e.gif'
When you refer to an image by its name, you must include
the form name if the image is on a form. The following code refers to the
image if it is on a form:
document.myForm.aircraft.src='f15e.gif'
Example 2: Create an image with the Image()
constructor. The following example creates an Image object,
myImage, that is 70 pixels wide and 50 pixels high. If the source
URL, seaotter.gif, does not have dimensions of 70x50 pixels,
it is scaled to that size.
myImage = new Image(70, 50)
myImage.src = "seaotter.gif"
If you omit the width and height arguments from the Image()
constructor, myImage is created with dimensions equal to that of the
image named in the source URL.
myImage = new Image()
myImage.src = "seaotter.gif"
Example 3: Display an image based on form input.
In the following example, the user selects which image is displayed. The
user orders a shirt by filling out a form. The image displayed depends on
the shirt color and size that the user chooses. All possible image choices
are pre-loaded to speed response time. When the user clicks the button to
order the shirt, the allShirts function displays the images of all
the shirts.
<SCRIPT>
shirts = new Array()
shirts[0] = "R-S"
shirts[1] = "R-M"
shirts[2] = "R-L"
shirts[3] = "W-S"
shirts[4] = "W-M"
shirts[5] = "W-L"
shirts[6] = "B-S"
shirts[7] = "B-M"
shirts[8] = "B-L"
doneThis = 0
shirtImg = new Array()
// Preload shirt images
for(idx=0; idx < 9; idx++) {
shirtImg[idx] = new Image()
shirtImg[idx].src = "shirt-" + shirts[idx] + ".gif"
}
function changeShirt(form)
{
shirtColor = form.color.options[form.color.selectedIndex].text
shirtSize = form.size.options[form.size.selectedIndex].text
newSrc = "shirt-" + shirtColor.charAt(0) + "-" + shirtSize.charAt(0) + ".gif"
document.shirt.src = newSrc
}
function allShirts()
{
document.shirt.src = shirtImg[doneThis].src
doneThis++
if(doneThis != 9)setTimeout("allShirts()", 500)
else doneThis = 0
return
}
</SCRIPT>
<FONT SIZE=+2><B>Netscape Polo Shirts!</FONT></B>
<TABLE CELLSPACING=20 BORDER=0>
<TR>
<TD><IMG name="shirt" SRC="shirt-W-L.gif"></TD>
<TD>
<FORM>
<B>Color</B>
<SELECT SIZE=3 NAME="color" onChange="changeShirt(this.form)">
<OPTION> Red
<OPTION SELECTED> White
<OPTION> Blue
</SELECT>
<P>
<B>Size</B>
<SELECT SIZE=3 NAME="size" onChange="changeShirt(this.form)">
<OPTION> Small
<OPTION> Medium
<OPTION SELECTED> Large
</SELECT>
<P><INPUT type="button" name="buy" value="Buy This Shirt!"
onClick="allShirts()">
</FORM>
</TD>
</TR>
</TABLE>
Example 4: JavaScript animation. The following example
uses JavaScript to create an animation with an Image object by repeatedly
changing the value the src property. The script begins by preloading
the 10 images that make up the animation (image1.gif,
image2.gif, image3.gif, and so on). When the
Image object is placed on the document with the <IMG> tag,
image1.gif is displayed and the onLoad event handler starts
the animation by calling the animate function. Notice that the
animate function does not call itself after changing the src
property of the Image object. This is because when the src
property changes, the image's onLoad event handler is triggered and the
animate function is called.
<SCRIPT>
delay = 100
imageNum = 1
// Preload animation images
theImages = new Array()
for(i = 1; i < 11; i++) {
theImages[i] = new Image()
theImages[i].src = "image" + i + ".gif"
}
function animate() {
document.animation.src = theImages[imageNum].src
imageNum++
if(imageNum > 10) {
imageNum = 1
}
}
function slower() {
delay+=10
if(delay > 4000) delay = 4000
}
function faster() {
delay-=10
if(delay < 0) delay = 0
}
</SCRIPT>
<BODY BGCOLOR="white">
<IMG NAME="animation" SRC="image1.gif" ALT="[Animation]"
onLoad="setTimeout('animate()', delay)">
<FORM>
<INPUT TYPE="button" Value="Slower" onClick="slower()">
<INPUT TYPE="button" Value="Faster" onClick="faster()">
</FORM>
</BODY>
See also the examples for the
onAbort,
onError, and
onLoad event handlers.
Link object;
onClick,
onMouseOut,
onMouseOver event handlers
Property. An array reflecting all the images in a document
in source order. See the Image object for
information.
index ">
Property. An integer representing the index of an option
in a Select object.
1. selectName.options[indexValue].index
2. optionName.index
selectName is either the value of the NAME attribute
of a Select object or an element in the elements array.
indexValue is an integer representing an option in
a Select object.
optionName is the name of a Select object
option created using the Option() constructor.
Option object (see the Select
object), options array (see the
Select object)
-
-
Navigator 2.0
-
Navigator 3.0: property of Option
No
The number identifying the position of the option in the
selection, starting from zero.
defaultSelected,
selected,
selectedIndex properties
Method. Returns the index within the calling String
object of the first occurrence of the specified value, starting the search
at fromIndex.
stringName.indexOf(searchValue, [fromIndex])
stringName is any string or a property of an existing
object.
searchValue is a string or a property of an existing
object, representing the value to search for.
fromIndex is the location within the calling string
to start the search from. It can be any integer from zero to
stringName.length - 1 or a property of an existing object.
String
Navigator 2.0
Characters in a string are indexed from left to right. The
index of the first character is zero, and the index of the last character
is stringName.length - 1.
If you do not specify a value for fromIndex, JavaScript
assumes zero by default. If searchValue is not found, JavaScript returns
-1.
If stringName contains an empty string (""),
indexOf returns an empty string.
The indexOf method is case sensitive. For example,
the following expression returns -1:
"Blue Whale".indexOf("blue")
Example 1. The following example uses indexOf
and lastIndexOf to locate values in the string "Brave new world."
var anyString="Brave new world"
//Displays 8
document.write("<P>The index of the first w from the beginning is " +
anyString.indexOf("w"))
//Displays 10
document.write("<P>The index of the first w from the end is " +
anyString.lastIndexOf("w"))
//Displays 6
document.write("<P>The index of 'new' from the beginning is " +
anyString.indexOf("new"))
//Displays 6
document.write("<P>The index of 'new' from the end is " +
anyString.lastIndexOf("new"))
Example 2. The following example defines two string
variables. The variables contain the same string except that the second string
contains uppercase letters. The first writeln method displays 19.
But because the indexOf method is case sensitive, the string "cheddar"
is not found in myCapString, so the second writeln method displays
-1.
myString="brie, pepper jack, cheddar"
myCapString="Brie, Pepper Jack, Cheddar"
document.writeln('myString.indexOf("cheddar") is ' +
myString.indexOf("cheddar"))
document.writeln('<P>myCapString.indexOf("cheddar") is ' +
myCapString.indexOf("cheddar"))
charAt,
lastIndexOf,
split methods
isNaN ">
Function. Evaluates an argument to determine if it is "NaN"
(not a number).
isNaN(testValue)
testValue is the value you want to evaluate.
-
-
Navigator 2.0
-
Navigator 3.0: works on all platforms (in previous releases, worked only
on Unix platforms)
isNaN is a built-in JavaScript function. It is not
a method associated with any object, but is part of the language itself.
On platforms that support NaN, the parseFloat and
parseInt functions return "NaN" when they evaluate a value that is
not a number. isNaN returns true if passed "NaN," and false
otherwise.
The following example evaluates floatValue to determine
if it is a number and then calls a procedure accordingly:
floatValue=parseFloat(toFloat)
if (isNaN(floatValue)) {
notFloat()
} else {
isFloat()
}
NaN property;
parseFloat,
parseInt functions
Method. Causes a string to be italic, as if it were in an
<I> tag.
stringName.italics()
stringName is any string or a property of an existing
object.
String
Navigator 2.0
Use the italics method with the write or
writeln methods to format and display a string in a document.
The following example uses string methods to change
the formatting of a string:
var worldString="Hello, world"
document.write(worldString.blink())
document.write("<P>" + worldString.bold())
document.write("<P>" + worldString.italics())
document.write("<P>" + worldString.strike())
The previous example produces the same output as the following
HTML:
<BLINK>Hello, world</BLINK>
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>
blink,
bold, strike
methods
Method. Specifies whether Java is enabled.
navigator.javaEnabled()
navigator
Navigator 3.0
javaEnabled returns true if Java is enabled, false
otherwise. The user can enable or disable Java by choosing Network Preferences
from the Navigator's Options menu.
The following code executes function1 if Java is
enabled; otherwise it executes function2.
if (navigator.javaEnabled()) {
function1()
}
else function2()
appCodeName,
appName,
userAgent properties
Method. Joins all elements of an array into a string.
arrayName.join(separator)
arrayName is the name of an Array object or
a property of an existing object.
separator specifies a string to separate each element
of the array. The separator is converted to a string if necessary.
If omitted, the array elements are separated with a comma (,).
Array
Navigator 3.0
The string conversion of all array elements are joined into
one string.
The following example creates an array, a with three
elements, then joins the array three times: using the default separator,
then a comma and a space, and then a plus.
a = new Array("Wind","Rain","Fire")
document.write(a.join() +"<BR>")
document.write(a.join(", ") +"<BR>")
document.write(a.join(" + ") +"<BR>")
This code produces the following output:
Wind,Rain,Fire
Wind, Rain, Fire
Wind + Rain + Fire
reverse,
sort methods
Method. Returns the index within the calling String
object of the last occurrence of the specified value. The calling string
is searched backward, starting at fromIndex.
stringName.lastIndexOf(searchValue, [fromIndex])
stringName is any string or a property of an existing
object.
searchValue is a string or a property of an existing
object, representing the value to search for.
fromIndex is the location within the calling string
to start the search from. It can be any integer from zero to
stringName.length - 1 or a property of an existing object.
String
Navigator 2.0
Characters in a string are indexed from left to right. The
index of the first character is zero, and the index of the last character
is stringName.length - 1.
If you do not specify a value for fromIndex, JavaScript
assumes stringName.length - 1 (the end of the string) by default.
If searchValue is not found, JavaScript returns -1.
The lastIndexOf method is case sensitive. For example,
the following expression returns -1:
"Blue Whale, Killer Whale".lastIndexOf("blue")
The following example uses indexOf and
lastIndexOf to locate values in the string "Brave new world."
var anyString="Brave new world"
//Displays 8
document.write("<P>The index of the first w from the beginning is " +
anyString.indexOf("w"))
//Displays 10
document.write("<P>The index of the first w from the end is " +
anyString.lastIndexOf("w"))
//Displays 6
document.write("<P>The index of 'new' from the beginning is " +
anyString.indexOf("new"))
//Displays 6
document.write("<P>The index of 'new' from the end is " +
anyString.lastIndexOf("new"))
charAt,
indexOf, split
methods
Property. A string representing the date that a document
was last modified.
document.lastModified
document
Navigator 2.0
Yes
The lastModified property is derived from the HTTP
header data sent by the web server. Servers generally obtain this date by
examining the file's modification date.
The last modified date is not a required portion of the
header, and some servers do not supply it. If the server does not return
the last modified information, JavaScript receives a zero, which it displays
as January 1, 1970 GMT. The following code checks the date returned by
lastModified and prints out a value that corresponds to unknown.
lastmod = document.lastModified // get string of last modified date
lastmoddate = Date.parse(lastmod) // convert modified string to date
if(lastmoddate == 0){ // unknown date (or January 1,
// 1970 GMT)
document.writeln("Lastmodified: Unknown")
} else {
document.writeln("LastModified: " + lastmod)
}
lastModified is a read-only property.
In the following example, the lastModified property
is used in a <SCRIPT> tag at the end of an HTML file to display the
modification date of the page:
document.write("This page updated on " + document.lastModified)
Property. An integer that specifies a length-related feature
of the calling object or array.
When used with objects:
1. formName.length
2. frameReference.length
3. history.length
4. radioName.length
5. selectName.length
6. stringName.length
7. windowReference.length
8. arrayName.length
When used with array properties:
9. anchors.length
10. applets.length
11. arguments.length
12. elements.length
13. embeds.length
14. forms.length
15. frames.length
16. history.length
17. images.length
18. links.length
19. mimeTypes.length
20. plugins.length
21. plugins[mimeTypeIndex].length
22. selectName.options.length
formName is either the name of a form or an element
in the forms array.
frameReference is either the value of the NAME attribute
of a frame or an element in the frames array.
radioName is either the value of the NAME attribute
of a Radio object or an element in the elements array.
selectName is either the value of the NAME attribute
of a Select object or an element in the elements array.
stringName is any string or a property of an existing
object.
windowReference is a valid way of referring to a
window, as described in the window
object.
arrayName is the name of an Array object.
mimeTypeIndex is either an integer representing
a MIME type supported by the plug-in or a string containing the type of a
MimeType object (from the type property).
Property
of">
-
-
Array object,
Frame object,
history object,
Radio object,
Select object,
String object, window
object
-
anchors array,
arguments array,
elements array,
forms array,
frames array,
images array,
links array,
mimeTypes array, options array (see
Select object),
plugins array
-
Navigator 2.0
-
Navigator 3.0: property of applets array, Array object,
embeds array, history array, images array,
mimeTypes array, plugins array
No
The length property is an integer that specifies
one of the following:
-
-
The number of elements on a form (form 1 of the syntax).
-
The number of frames within a frame (form 2 of the syntax). A frame that
does not load a document containing a <FRAMESET> tag always has a length
of zero.
-
The number of entries in a history object (form 3 of the syntax).
-
The number of radio buttons in a Radio object (form 4 of the syntax).
-
The number of options in a Select object (form 5 of the syntax).
-
The length of a String object (form 6 of the syntax).
-
The number of frames in a parent window (form 7 of the syntax).
-
The number of elements in an array (form 8 of the syntax).
-
The number of MIME types supported by the client (form 19 of the syntax).
-
The number of plug-in modules installed on the client (form 20 of the syntax).
-
The number of elements in a Plugin object's array of MimeType
objects (form 21 of the syntax).
-
The number of entries in one of the array properties (all other syntax
forms).
For all objects except Array objects, length
is always a read-only property.
For a null string, length is zero. For a Select
object, the values returned by form 5 and form 22 of the syntax are the same.
For a window containing frames, the values returned by form 7 and form 15
of the syntax are the same. For a Form object, the values returned
by form 1 and form 12 of the syntax are the same. For a frame containing
frames, the values returned by form 2 and form 15 of the syntax are the
same.
For arrays, you can set the length property to truncate
an array at any time. You cannot extend an array; for example, if you set
length to 3 when it is currently 2, the array will still contain only 2 elements.
For information on other ways to change the length of an array, see the
Array object.
In the following example, the getChoice function
uses the length property to iterate over every element in the
musicType array. musicType is a select element on the
musicForm form.
function getChoice() {
for (var i = 0; i < document.musicForm.musicType.length; i++) {
if (document.musicForm.musicType.options[i].selected == true) {
return document.musicForm.musicType.options[i].text
}
}
}
The following example displays 8 in an Alert dialog box:
var x="Netscape"
alert("The string length is " + x.length)
The following example shortens the array statesUS
to a length of 50 if the current length is greater than 50.
if (statesUS.length > 50) {
statesUS.length=50
alert("The U.S. has only 50 states. New length is " + statesUS.length)
}
Method. Creates an HTML hypertext link that requests another
URL.
linkText.link(hrefAttribute)
linkText is any string or a property of an existing
object. This represents the text that will be displayed in the link.
hrefAttribute is any string that specifies the HREF
attribute of the <A> tag; it should be a valid URL (relative or
absolute).
String
Navigator 2.0
Use the link method to programmatically create a hypertext
link, and then call write or writeln to display the link in
a document.
Links created with the link method become elements
in the links array. See the Link object
for information about the links array.
The following example displays the word "Netscape" as a hypertext
link that returns the user to the Netscape home page:
var hotText="Netscape"
var URL="http://home.netscape.com"
document.write("Click to return to " + hotText.link(URL))
The previous example produces the same output as the following
HTML:
Click to return to <A HREF="http://home.netscape.com">Netscape</A>
Anchor object
Object. A piece of text, an image, or an area of an image
identified as a hypertext link. When the user clicks the link text, image,
or area, the link hypertext reference is loaded into its target window.
Area objects are a type of Link object.
To define a link, use standard HTML syntax with the addition
of JavaScript event handlers:
<A HREF=locationOrURL
[NAME="anchorName"]
[TARGET="windowName"]
[onClick="handlerText"]
[onMouseOut="handlerText"]>
[onMouseOver="handlerText"]>
linkText
</A>
You can also define a link using the
link method.
To define an area, use standard HTML syntax with the addition
of JavaScript event handlers:
<MAP NAME="mapName">
<AREA
[NAME="areaName"]
COORDS="x1,y1,x2,y2,..."|"x-center,y-center,radius"
HREF="locationOrURL"
[SHAPE="rect"|"poly"|"circle"|"default"]
[TARGET="windowName"]
[onMouseOut="handlerText"]
[onMouseOver="handlerText"]>
</MAP>
HREF=locationOrURL identifies a destination anchor
or URL. For areas, any region of an image that does not have an HREF attribute
does not function as a hyperlink. For areas, this attribute is required if
you include the onMouseOut and onMouseOver event handlers. See the
location object for a description
of the URL components.
NAME="anchorName" is used only if the link is also
an anchor. It specifies a name for the anchor that then becomes an available
hypertext target within the current document. See the
Anchor object for details.
TARGET="windowName" specifies the frame or window
that the link is loaded into. windowName can be an existing window;
it can be a frame name specified in a <FRAMESET> tag; or it can be
one of the literal frame names _top, _parent, _self, or _blank. It cannot
be a JavaScript expression (for example, it cannot be parent.frameName
or windowName.frameName).
linkText is the text or HTML source that the user
sees as a hypertext link to the URL.
NAME="mapName" specifies the name of the map. You
can specify this map name in the USEMAP attribute of the <IMG> tag.
AREA defines an area of an image as an image map.
NAME="areaName" specifies the name of the
Area object. This attribute is not reflected in JavaScript (you cannot
refer to an Area object by name).
COORDS specifies the coordinates of the image map.
SHAPE specifies the shape of the map. "default"
specifies a region as the default. If omitted, "rect" is used.
To use a Link or Area object's properties:
document.links[index].propertyName
index is an integer representing a Link or
Area object or the name of a Link or Area object as
specified by the NAME attribute.
propertyName is one of the properties listed below.
document
-
-
Navigator 2.0
-
Navigator 3.0: added onMouseOut event handler; added Area objects;
links array contains areas created with <AREA HREF="...">
Each Link object is a location object and
has the same properties as a location object.
If a Link object is also an Anchor object,
the object has entries in both the anchors and links arrays.
When a user clicks a Link object and navigates to
the destination document (specified by HREF=locationOrURL), the
destination document's referrer property contains the URL of the source
document. Evaluate the referrer property from the destination
document.
You can use a Link object to execute a JavaScript
function rather than link to a hypertext reference by specifying the
javascript: URL protocol for the link's HREF attribute. You
might want to do this if the link surrounds an Image object and you
want to execute JavaScript code when the image is clicked. Or you might want
to use a link instead of a button to execute JavaScript code.
For example, when a user clicks the following links, the
slower and faster functions execute:
<A HREF="javascript:slower()">Slower</A>
<A HREF="javascript:faster()">Faster</A>
You can use a Link object to do nothing rather than
link to a hypertext reference by specifying the
javascript:void(0) URL protocol for the link's HREF attribute.
You might want to do this if the link surrounds an Image object and
you want to use the link's event handlers with the image. When a user clicks
the following link or image, nothing happens:
<A HREF="javascript:void(0)">Click here to do nothing</A>
<A HREF="javascript:void(0)">
<IMG SRC="images\globe.gif" ALIGN="top" HEIGHT="50" WIDTH="50">
</A>
Area objects are in the links array. You
cannot refer to an Area object by name; you must use the links
array. For example, if a document contains three Area objects, these
objects are reflected as document.links[0],
document.links[1], and document.links[2]. For
information on the links array, see "The links
array".
The HREF attribute is required for Area objects
that use the onMouseOut or onMouseOver event handlers. However, if you create
an Area for an image and do not want the image to link to a hypertext
reference when clicked, specify a JavaScript function in the area's HREF
attribute by using the javascript: URL protocol. For example,
if a user clicks the following Area object, the function onTop
executes.
<MAP NAME="worldMap">
<AREA NAME="topWorld" COORDS="0,0,50,25" HREF="javascript:onTop()"
onMouseOver="self.status='You are on top of the world';return true"
onMouseOut="self.status='You have left the top of the world';return true">
</MAP>
If you want an area's link to do nothing, use
javascript:void(0) in the HREF attribute. When the user clicks
the following Area object, nothing happens:
<MAP NAME="worldMap">
<AREA NAME="topWorld" COORDS="0,0,50,25" HREF="javascript:void(0)"
onMouseOver="self.status='You are on top of the world';return true"
onMouseOut="self.status='You have left the top of the world';return true">
</MAP>
links array ">
You can reference the Area and Link objects
in your code by using the links array. This array contains an entry
for each Area (<AREA HREF="..."> tag) and Link (<A
HREF=""> tag) object in a document in source order. It also contains links
created with the link method.For example, if a document contains three
Link objects, these links are reflected as
document.links[0], document.links[1], and
document.links[2].
To use the links array:
1. document.links[index]
2. document.links.length
index is an integer representing a link in a document
or the name of a Link object as specified by the NAME attribute.
To obtain the number of links in a document, use the
length property: document.links.length.
Elements in the links array are read-only. For example,
the statement document.links[0]="link1" has no effect.
The Area and Link objects have the following
properties:
The links array has the following property:
Area objects have the following event handlers:
Link objects have the following event handlers:
Example 1. The following example creates a hypertext
link to an anchor named javascript_intro:
<A HREF="#javascript_intro">Introduction to JavaScript</A>
Example 2. The following example creates a hypertext
link to an anchor named numbers in the file doc3.html
in the window window2. If window2 does not exist, it is
created.
<LI><A HREF=doc3.html#numbers TARGET="window2">Numbers</A>
Example 3. The following example takes the user back
x entries in the history list:
<A HREF="javascript:history.go(-1 * x)">Click here</A>
Example 4. The following example creates a hypertext
link to a URL. The user can use the set of radio buttons to choose between
three URLs. The link's onClick event handler sets the URL (the link's
href property) based on the selected radio button. The link also has
an onMouseOver event handler that changes the window's status property.
As the example shows, you must return true to set the
window.status property in the onMouseOver event handler.
<SCRIPT>
var destHREF="http://home.netscape.com/"
</SCRIPT>
<FORM NAME="form1">
<B>Choose a destination from the following list, then click "Click me" below.</B>
<BR><INPUT TYPE="radio" NAME="destination" VALUE="netscape"
onClick="destHREF='http://home.netscape.com/'"> Netscape home page
<BR><INPUT TYPE="radio" NAME="destination" VALUE="sun"
onClick="destHREF='http://www.sun.com/'"> Sun home page
<BR><INPUT TYPE="radio" NAME="destination" VALUE="rfc1867"
onClick="destHREF='http://www.ics.uci.edu/pub/ietf/html/rfc1867.txt'"> RFC 1867
<P><A HREF=""
onMouseOver="window.status='Click this if you dare!'; return true"
onClick="this.href=destHREF">
<B>Click me</B></A>
</FORM>
Example 5: links array. In the following example,
the linkGetter function uses the links array to display the
value of each link in the current document. The example also defines several
links and a button for running linkGetter.
function linkGetter() {
msgWindow=window.open("","msg","width=400,height=400")
msgWindow.document.write("links.length is " +
document.links.length + "<BR>")
for (var i = 0; i < document.links.length; i++) {
msgWindow.document.write(document.links[i] + "<BR>")
}
}
<A HREF="http://home.netscape.com">Netscape Home Page</A>
<A HREF="http://www.catalog.com/fwcfc/">China Adoptions</A>
<A HREF="http://www.supernet.net/~dugbrown/">Bad Dog Chronicles</A>
<A HREF="http://www.best.com/~doghouse/homecnt.shtml">Lab Rescue</A>
<P>
<INPUT TYPE="button" VALUE="Display links"
onClick="linkGetter()">
Example 6: Area object with onMouseOver and onMouseOut
event handlers. The following example displays an image,
globe.gif. The image uses an image map that defines areas for
the top half and the bottom half of the image. The onMouseOver and onMouseOut
event handlers display different status bar messages depending on whether
the mouse passes over or leaves the top half or bottom half of the image.
The HREF attribute is required when using the onMouseOver and onMouseOut
event handlers, but in this example the image does not need a hypertext link,
so the HREF attribute executes javascript:void(0), which does
nothing (see "void" for more information).
<MAP NAME="worldMap">
<AREA NAME="topWorld" COORDS="0,0,50,25" HREF="javascript:void(0)"
onMouseOver="self.status='You are on top of the world';return true"
onMouseOut="self.status='You have left the top of the world';return true">
<AREA NAME="bottomWorld" COORDS="0,25,50,50" HREF="javascript:void(0)"
onMouseOver="self.status='You are on the bottom of the world';return true"
onMouseOut="self.status='You have left the bottom of the world';return true">
</MAP>
<IMG SRC="images\globe.gif" ALIGN="top" HEIGHT="50" WIDTH="50" USEMAP="#worldMap">
Example 7: Refer to Area object with links array.
The following code refers to the href property of the first
Areaobject shown in Example 1.
document.links[0].href
Example 8: Simulate an Area object's onClick using the
HREF attribute. The following example uses an Area object's HREF
attribute to execute a JavaScript function. The image displayed,
colors.gif, shows two sample colors. The top half of the image
is the color "antiquewhite", and the bottom half is "white". When the user
clicks the top or bottom half of the image, the function setBGColor
changes the document's background color to the color shown in the image.
<SCRIPT>
function setBGColor(theColor) {
document.bgColor=theColor
}
</SCRIPT>
Click the color you want for this document's background color
<MAP NAME="colorMap">
<AREA NAME="topColor" COORDS="0,0,50,25" HREF="javascript:setBGColor('antiquewhite')">
<AREA NAME="bottomColor" COORDS="0,25,50,50" HREF="javascript:setBGColor('white')">
</MAP>
<IMG SRC="images\colors.gif" ALIGN="top" HEIGHT="50" WIDTH="50" USEMAP="#colorMap">
Anchor object,
Image object; link
method
Property. A string specifying the color of the document
hyperlinks.
document.linkColor
document
Navigator 2.0
No
The linkColor property is expressed as a hexadecimal
RGB triplet or as one of the string literals listed in
"Color values". This property is the JavaScript
reflection of the LINK attribute of the <BODY> tag. The default value
of this property is set by the user on the Colors tab of the Preferences
dialog box, which is displayed by choosing General Preferences from the Options
menu. You cannot set this property after the HTML source has been through
layout.
If you express the color as a hexadecimal RGB triplet, you
must use the format rrggbb. For example, the hexadecimal RGB values for salmon
are red=FA, green=80, and blue=72, so the RGB triplet for salmon is
"FA8072."
The following example sets the color of document links to
aqua using a string literal:
document.linkColor="aqua"
The following example sets the color of document links to
aqua using a hexadecimal triplet:
document.linkColor="00FFFF"
alinkColor,
bgColor,
fgColor,
vlinkColor properties
Property. An array of objects corresponding to Area
and Link objects in source order. See the
Link object for information.
Yes
Property. The natural logarithm of two, approximately 0.693.
Math.LN2
Math
Navigator 2.0
No
Because LN2 is a constant, it is a read-only property of
Math.
The following function returns the natural log of two:
function getNatLog2() {
return Math.LN2
}
E,
LN10, LOG2E,
LOG10E, PI,
SQRT1_2, SQRT2
properties
Property. The natural logarithm of 10, approximately 2.302.
Math.LN10
Math
Navigator 2.0
No
Because LN10 is a constant, it is a read-only property of
Math.
The following function returns the natural log of 10:
function getNatLog10() {
return Math.LN10
}
E,
LN2, LOG2E,
LOG10E, PI,
SQRT1_2, SQRT2
properties
Object. Contains information on the current URL.
To use a location object:
[windowReference.]location[.propertyName]
[windowReference.]location.methodName(parameters)
windowReference is a variable windowVar from
a window definition (see the window object),
or one of the synonyms top or parent.
propertyName is one of the properties listed below.
Omitting the property name is equivalent to specifying the href property
(the complete URL).
methodName is one of the methods listed below.
window object
-
-
Navigator 2.0
-
Navigator 3.0: added reload, replace methods; changed the way documents
are loaded when location is set
The location object represents a complete URL. Each
property of the location object represents a different portion of
the URL.
The following diagram of a URL shows the relationships between
the location properties:
protocol//host:port/pathname#hash?search
For example:
http://home.netscape.com/assist/extensions.html#topic1?x=7&y=2
Following is a description of each part of the URL
diagram:
-
-
protocol represents the beginning of the URL, up to and including
the first colon.
-
host represents the host and domain name, or IP address, of a network
host.
-
port represents the communications port that the server uses for
communications.
-
pathname represents the url-path portion of the URL.
-
hash represents an anchor name fragment in the URL, including the
hash mark (#). This property applies to http URLs only.
-
search represents any query information in the URL, including the
question mark (?). This property applies to http URLs only. The search string
contains variable and value pairs; each pair is separated by an ampersand
(&).
See the properties (listed below) for details about the
different parts of the URL, or the href property
for examples.
The location object has two other properties not
shown in the diagram above:
-
-
href represents a complete URL.
-
hostname represents the concatenation host:port.
Omitting a property name from the location object
is equivalent to specifying location.href. For example, the
following two statements are equivalent and set the URL of the current window
to the Netscape home page:
window.location.href="http://home.netscape.com/"
window.location="http://home.netscape.com/"
The location object is contained by the
window object and is within its scope. If you reference a
location object without specifying a window, the location object
represents the current location. If you reference a location object
and specify a window name, for example,
windowReference.location
.propertyName, the location object represents the location
of the specified window.
In event handlers, you must specify
window.location instead of simply using location.
Due to the scoping of static objects in JavaScript, a call to
location without specifying an object name is equivalent to
document.location, which is a synonym for
document.URL.
Do not use location as a property of the
document object; use the document.URL property instead. The
document.location property, which is a synonym for
document.URL, will be removed in a future release.
When you set the location object or any of its
properties except hash, whether a new document is loaded depends on
which version of Navigator you are running:
-
-
In Navigator 2.0, setting location does a conditional
("If-modified-since") HTTP GET operation, which returns no data from the
server unless the document has been modified since the last version downloaded.
-
In Navigator 3.0, the effect of setting location depends on the user's
setting for verifying documents. (The user chooses Network Preferences from
the Options menu and on the Cache tab, specifies one of the following for
Verify Documents: Once Per Session, Every Time, or Never.) The document is
reloaded from cache if the user sets Never or Once Per Session; the document
is reloaded from the server only if the user chooses Every Time.
When you specify a URL, you can use standard URL formats
and JavaScript statements. The following list shows the syntax for specifying
some of the most common types of URLs.
The javascript: protocol evaluates the expression after
the colon (:), if there is one, and loads a page containing the string value
of the expression, unless it is undefined. If the expression evaluates to
undefined (by calling a void function, for example
javascript:void(0)), no new page loads. Note that loading a
new page over your script's page clears the page's variables, functions,
and so on.
The view-source: protocol displays HTML code that was generated
with JavaScript write and
writeln methods. For information on
printing and saving generated HTML, see the
write method.
The about: protocol provides information on Navigator and
has the following syntax:
about:[cache|plugins]
-
-
about: by itself is the same as choosing About Netscape from the Navigator
Help menu.
-
about:cache displays disk-cache statistics.
-
about:plugins displays information about plug-ins you have configured.
This is the same as choosing About Plug-ins from the Navigator Help menu.
The location object has the following properties:
The location object has the following methods:
None.
Example 1. The following two statements are equivalent
and set the URL of the current window to the Netscape home page:
window.location.href="http://home.netscape.com/"
window.location="http://home.netscape.com/"
Example 2. The following statement sets the URL of
a frame named frame2 to the Sun home page:
parent.frame2.location.href="http://www.sun.com/"
See also the examples for the
Anchor object.
history object;
URL property
Method. Returns the natural logarithm (base e) of
a number.
Math.log(number)
number is any positive numeric expression or a property
of an existing object.
Math
Navigator 2.0
If the value of number is outside the suggested range,
the return value is always -1.797693134862316e+308.
The following function returns the natural log of the variable
x:
function getLog(x) {
return Math.log(x)
}
If you pass getLog the value 10, it returns
2.302585092994046; if you pass it the value zero, it returns
-1.797693134862316e+308 because zero is out of range.
exp,
pow methods
Property. The base 2 logarithm of e (approximately 1.442).
Math.LOG2E
Math
Navigator 2.0
No
Because LOG2E is a constant, it is a read-only property
of Math.
The following function returns the base 2 logarithm of E:
function getLog2e() {
return Math.LOG2E
}
E,
LN2, LN10,
LOG10E, PI,
SQRT1_2, SQRT2
properties
Property. The base 10 logarithm of e (approximately 0.434).
Math.LOG10E
Math
Navigator 2.0
No
Because LOG10E is a constant, it is a read-only property
of Math.
The following function returns the base 10 logarithm of
E:
function getLog10e() {
return Math.LOG10E
}
E,
LN2, LN10,
LOG2E, PI,
SQRT1_2, SQRT2
properties
Property. A string specifying the URL of a low-resolution
version of an image to be displayed in a document.
imageName.lowsrc
imageName is either the name of an Image object
or an element in the images array.
Image
Navigator 3.0
No
The lowsrc property initially reflects the LOWSRC
attribute of the <IMG> tag. Navigator loads the smaller image specified
by lowsrc and then replaces it with the larger image specified by
the src property. You can change the lowsrc property at any
time.
See the examples for the src
property.
complete,
src properties
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