Javascript function issue

Question

Hi i did some search about some function that i need , and i found it here on StackOverFlow . The problem is in all browsers i get "bug" on the script that says :

mouse_is_inside is not defined

But its defined ,and the function working perfect, and can't get rid from that message any advance?

I tryed though of that . but i dont know how to assume :

if (typeof variable === 'undefined') {
 // variable is undefined
}

My function :

$(document).ready(function()
{
 $('#contactbox').hover(function(){ 
 mouse_is_inside=true; 
 }, function(){ 
 mouse_is_inside=false; 
 });
 $("body").mouseup(function(){
 if(! mouse_is_inside) // the problem is here says not defined .
 {
 if ($.browser.msie && parseInt($.browser.version, 10) === 7) {
 $("#main").css('z-index','0');
 } 
 $('#contactb a').removeClass('cactive');
 $('#contactb a').addClass('cnoactive');
 $('#contactbox').hide()
 }
 });
});

EDIT thanks my bad , didnt know its so easy . i will tick the answer.

Answer 1

All you need is to add this line:

var mouse_is_inside = false;

...just inside the function. E.g.:

$(document).ready(function()
{
 var mouse_is_inside = false;
 // ...the rest of the code
});

Because the error is correct: You haven't defined it anywhere. But then the first time you do this:

mouse_is_inside=false;

or this:

mouse_is_inside=true;

...you're defining it, by falling prey to The Horror of Implicit Globals. In JavaScript's "loose" mode (the default), if you try to read the value of an undefined symbol, it's a ReferenceError; but if you write to an undefined symbol, it creates a global variable (implicitly). Fortunately, as of ES5, we have "strict" mode which makes both operations the errors they should be.

• PlaceUserNameHere: But the variable it's global isn't it, sorry to doubt but I noticed that
• T.J. Crowder: @PlaceUserNameHere: Yes, it is -- it's an implicit global, because it's not defined anywhere, but the OP is assigning to it.
• T.J. Crowder: @Ravg: Easy mistake to make. Check out strict mode, it's really useful to catch things like this (or typos, e.g., you declare the variable blarg but type blagr by mistake).

Answer 2

Add declaration of mouse_is_inside i.e.

$(document).ready(function () {
 var mouse_is_inside;
 $('#contactbox').hover(function () {
 mouse_is_inside = true;
 }, function () {
 mouse_is_inside = false;
 });
 $("body").mouseup(function () {
 if (!mouse_is_inside) // the problem is here says not defined .
 {
 if ($.browser.msie && parseInt($.browser.version, 10) === 7) {
 $("#main").css('z-index', '0');
 }
 $('#contactb a').removeClass('cactive');
 $('#contactb a').addClass('cnoactive');
 $('#contactbox').hide()
 }
 });
});