JavaScript Pocket Reference

The JavaScript Language

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allows instances of your class to be converted to strings. For

example:

// Define function literals and assign them

// to properties of the prototype object.

Point.prototype.distanceTo = function(that) {

var dx = this.x - that.x;

var dy = this.y - that.y;

return Math.sqrt(dx*dx + dy*dy);

}

Point.prototype.toString = function () {

return '(' + this.x + ',' + this.y + ')';

}

If you want to define static (or class) methods or properties,

you can assign them directly to the constructor function,

rather than to the prototype object. For example:

// Define a commonly used Point constant

Point.ORIGIN = new Point(0,0);

The preceding code fragments define a simple Point class

that we can use with code like this:

// Call constructor to create a new Point object

var p = new Point(3,4);

// Invoke a method of the object, using a static

// property as the argument.

var d = p.distanceTo(Point.ORIGIN);

// Adding the object to a string implicitly

// invokes toString().

var msg = "Distance to " + p + " is " + d;

Regular Expressions

JavaScript supports regular expressions for pattern matching

with the same syntax as the Perl programming language.

JavaScript 1.2 supports Perl 4 regular expressions, and Java-

Script 1.5 adds supports for some of the additional features

of Perl 5 regular expressions. A regular expression is speci-

fied literally in a JavaScript program as a sequence of charac-

ters within ...