AJAX - The Complete Reference

PART IV

Appendix A: JavaScript Quick Reference 565

Function Literals

Function literals are used with the following syntax:

function ([ args ])

{

statements

}

where args is a comma-separated list of identifiers for the function arguments, and statements

is zero or more valid JavaScript statements. Function literals are often found in constructors:

function Dog()

{

this.bark = function () {alert("woof!"); };

}

or when binding them to event handlers:

xhr.onreadystatechange = function () { alert("do something!"); };

or performing other higher-order programming tasks.

Although not strictly a literal, you can also use the Function() constructor.

new Function(["arg1", ["arg2"], ... ,] "statements");

The argNs are the names of the parameters the function accepts, and statements is the

body of the function. For example:

myArray.sort(new Function("name", "alert('Hello there ' + name) "));

Regular Expression Literals

Regular expression literals (actually RegExp literals) have the following syntax:

/exp/flags

where exp is a valid regular expression and flags is zero or more regular expression modifiers

for example, “gi” for global and case-insensitive.

Although not strictly a literal, you can use the RegExp() constructor inline in

JavaScript.

new RegExp("exp" [,"flags"])

Identifi ers

JavaScript identifiers start with either a letter, underscore, or dollar sign and can be followed

by any number of letters, digits, underscores, and dollar signs. Given this, the following are

legal identifiers being used as variables:

var myName = "Thomas";

var x = 33;

var _pleaseNo = true;

var $$$$ = "Big Money!";