JavaScript actually implements all objects as nothing but associative arrays. We can test this in the following example. In Javascript objects can be created in many ways as follows.
- Simple Object Creation
- The simplest way to create an object is using keyword new Object().
var simpleObject = new Object();
simpleObject.firstName = 'Foo';
simpleObject.lastName = 'Bar';
simpleObject.alertName = function()
{
alert('My Name is : ' + this.firstName + ' ' + this.lastName);
}If we call simpleObject.alertName() or simpleObject.[‘alertName’]() it will alert the firstName and lastName using concatenation
- JSON
- Basically we use JSON with the Ajax Request. But JSON is actually a core part of Javascript Specification. Lets build the previous example using JSON.
var JSONObject =
{
firstName : "Foo",
lastName : "Bar",
alertName : function()
{
alert('My Name is : ' + this.firstName + ' ' + this.lastName);
}
};- Now if we call JSONObject.alertName() , the same output will be alerted as the previous one.
- Prototype
- Every single object in JavaScript has a prototype property associated with it. the way it works is that when you construct a new instance of an object, all the properties and methods defined in the prototype of the object are attached to the new instance at runtime
function PrototypeClass()
{
this.firstName = 'Foo';
this.lastName = 'Bar';
}
PrototypeClass.prototype.alertName = function()
{
alert('My Name is : ' + this.firstName + ' ' + this.lastName);
}
var prototypeObject = new PrototypeClass();
prototypeObject.alertName(); // it will produce the same output as in the previous example.
Reference : “Practical JavaScript™,DOM Scripting and Ajax Projects”