ExtJs

Javascript原始的继承写法：

Javascript代码

1. // Traditional constructor:   
2. Ext.Foo = function(config){   
3.     // call superclass constructor:   
4.     Ext.Foo.superclass.constructor.call(this, config);   
5.   
6.     this.addEvents({   
7.         // add events   
8.     });   
9. };   
10. Ext.extend(Ext.Foo, Ext.Bar, {   
11.    // class body   
12. }  

// Traditional constructor:
Ext.Foo = function(config){
	// call superclass constructor:
    Ext.Foo.superclass.constructor.call(this, config);

    this.addEvents({
		// add events
    });
};
Ext.extend(Ext.Foo, Ext.Bar, {
   // class body
}

Extjs中替换constructor，写法如下：

Javascript代码

1. // initComponent replaces the constructor:   
2. Ext.Foo = Ext.extend(Ext.Bar, {   
3.     initComponent : function(){   
4.         // call superclass initComponent   
5.         Ext.Container.superclass.initComponent.call(this);   
6.   
7.         this.addEvents({   
8.             // add events   
9.         });   
10.     }   
11. }  

 

1. Ext.extend adds the superclass property to the prototype of subclass (=the prototype of class you are extending from).
2. Ext.extend also adds a constructor property to the prototype of the subclass (=the class itself). It also adds a contructor to the prototype of the superclass if it is an Object.
3. With method.call(obj) you can execute a method in a specified scope (this=obj).