Ext.Define function is a part of EXTJs. ExtJS is a advance javascript framework, It used to create java class and their method by using javascript.

I write the Ext.define method below :

Ext.define ( String className, Object data, Function createdFn ) : Ext.Base

Ext.define is used to define a class.

Example:

creates My.computer.NoteBook Class

Ext.define('My.computer.NoteBook', {

     extend:'Ext.panel.Panel',

     config: {

          hardware:'Dell',
          os:'Linux',
          price:500
     },

     constructor:function(config) {

          this.initConfig(config);

          return this;
     }
});

creates instance of My.computer.NoteBook Class

var myComputer = Ext.create('My.computer.NoteBook', {

     hardware:'MacBook Pro',
     os:'Mac OS X',
     price:1800
});