Programming Tutorials

By: Syed Fazal : 2008年08月16日

Description: One of the most frequently used statements in JavaScript (and indeed, in many languages), is the if statement. The if statement has the following syntax:

By: Syed Fazal : 2008年08月16日

Description: The logical AND operator in JavaScript is indicated by the double ampersand (&&):

By: Syed Fazal : 2008年08月15日

Description: The logical NOT operator in JavaScript is the same as in C and Java, indicated by an exclamation point (!). Unlike logical OR and logical AND operators, the logical NOT always returns a Boolean value.

By: Syed Fazal : 2008年08月15日

Description: The bitwise NOT is represented by a tilde (~) and is one of just a few ECMAScript operators related to binary mathematics. The bitwise NOT is a three-step process:

By: Emiley J. : 2008年08月15日

Description: It's also possible to convert values using a process called type casting. Type casting allows you to access a specific value as if it were of a different type. Three type casts are available in JavaScript: Type casting is very helpful when dealing with the loosely typed nature of JavaScript, although you should ensure that only proper values are used

By: Nicholas C. Zakas : 2008年08月15日

Description: JavaScript provides two methods for converting non-number primitives into numbers: parseInt() and parseFloat(). As you may have guessed, the former converts a value into an integer whereas the latter converts a value into a floating-point number. These methods only work properly when called on strings; all other types return NaN.

By: Nicholas C. Zakas : 2008年08月15日

Description: The interesting thing about JavaScript primitive values for Booleans, numbers, and strings is that they are pseudo-objects, meaning that they actually have properties and methods. For example, to get the length of a string, you can do the following:

By: Emiley J. : 2008年08月15日

Description: By rule, keywords are reserved and cannot be used as variable or function names. Here is the complete list of JavaScript keywords.

By: Nicholas C. Zakas : 2008年08月15日

Description: ECMAScript is the standard that set the basics of Javascript syntax. Developers familiar with languages such as Java, C, and Perl will find ECMAScript syntax easy to pick up because it borrows syntax from each. Java and ECMAScript have several key syntax features in common, as well as some that are completely different.

By: Nicholas C. Zakas : 2008年08月15日

Description: Around 1992, a company called Nombas began developing an embedded scripting language called C-minus-minus (Cmm for short). The idea behind Cmm was simple: a scripting language powerful enough to replace macros, but still similar enough to C (and C++) that developers could learn it quickly. This scripting language was packaged in a shareware product called CEnvi, which first exposed the power of such languages to developers. Nombas eventually changed the name Cmm to ScriptEase because the latter sounded "too negative" and the letter C "frightened people". ScriptEase is now the driving force behind Nombas products. When the popularity of Netscape Navigator started peaking, Nombas developed a version of CEnvi that could be embedded into Web pages. These early experiments were called Espresso Pages, and they represented the first client-side scripting language used on the World Wide Web. Little did Nombas know that its ideas would become an important foundation for the Internet.