javascript学习五

<script type="text/javascript">
	//使用call实现继承
	function parent(username){
		this.username=username;
		this.sayHello=function(){
			alert(this.username);
		}
	}
	
	function child(username,password){
		parent.call(this,username);
		this.password=password;
		this.sayWord=function(){
			alert(this.password);
		}
	}
	
	var p=new parent("hello");
	var c=new child("word","123");
	
	p.sayHello();
	
	c.sayHello();
	c.sayWord();
</script>

 apply方法方式：

<script type="text/javascript">
	//apply方法实现对象继承
	function parent(username){
		this.username=username;
		this.sayHello=function(){
			alert(this.username);
		}
	}
	
	function child(username,password){
		parent.apply(this,new Array(username));
		this.password=password;
		this.sayWord=function(){
			alert(this.password);
		}
	}
	
	var p=new parent("hello");
	var c=new child("word","123");
	
	p.sayHello();
	c.sayHello();
	c.sayWord();
</script>

 原型链方式：无法给构造函数传递参数

<script type="text/javascript">
	//使用原型链(prototype chain)实现对象的继承
	function parent(){}
	parent.prototype.hello="hello";
	parent.prototype.sayHello=function(){
		alert(this.hello);
	}
	
	function child(){}
	child.prototype=new parent();
	child.prototype.word="word";
	child.prototype.sayWord=function(){
		alert(this.word);
	}
	
	var p=new parent();
	var c=new child();
	p.sayHello();
	c.sayHello();
	c.sayWord();
</script>

 混合方式：（推荐使用）

<script type="text/javascript">
	//使用混合方式实现对象的继承
	function parent(hello){
		this.hello=hello;
	}
	parent.prototype.sayHello=function(){
		alert(this.hello);
	}
	
	function child(hello,word){
		//实现属性的继承
		parent.call(this,hello);
		this.word=word;
	}
	//实现方法的继承
	child.prototype=new parent();
	child.prototype.sayWord=function(){
		alert(this.word);
	}
	
	var p=new parent("hello");
	var c=new child("word","123");
	
	p.sayHello();
	c.sayHello();
	c.sayWord();
</script>

 学到这里，javascript的核心应该已经学完了，可是自己感觉没什么进步，不知道大家是怎么在学习啊，希望大家能指教指教小弟。