JavaScript原型對象原理與應用分析

function computer(){
   this.name="thinkPad 500";
   this.factory="聯(lián)想";
   this.price=5000;
   this.size=17;
}
/*
*讀取函數(shù)中的prototype,默認情況下為空
*/
for( pro in computer.prototype){
   document.write(computer.prototype,"<br>");
}
//沒有繼承原型對象中屬性
var mycomputer=new computer();
for( pro in mycomputer){
   document.write(pro,":",mycomputer[pro],"<br>");
}
computer.prototype.interface="VAG";
//添加原型對象的屬性
for( pro in computer.prototype){
   document.write(pro,":",computer.prototype[pro],"<br>");
}
//繼承原型對象中屬性
var mycomputer=new computer();
for( pro in mycomputer){
   document.write(pro,":",mycomputer[pro],"<br>");
}

<script type="text/javascript">
//定義一個工人
function worker(){
    this.name="";
    this.address="";
}
//定義一個部門經(jīng)理
function manager(_dept){
    this.dept=_dept;
}
//定義繼承關系
manager.prototype=new worker();
//創(chuàng)建計劃部門經(jīng)理
var jh=new manager("計劃");
for(pro in jh){
    document.write(pro,":",jh[pro],"<br>");
}
//當前jh有效沒有改變原型對象中的值
jh.name="計劃部門經(jīng)理";
jh.address="計劃部";
for(pro in jh){
    document.write(pro,":",jh[pro],"<br>");
}
//原型對象中的值沒有被修改
var rs=new manager('人事');
for(pro in rs){
    document.write(pro,":",rs[pro],"<br>");
}
//修改原型對象中的值，將會在繼承的對象中體現(xiàn),如果繼承類中沒有覆蓋
manager.prototype.address="成都市";
//覆蓋后address的值還是原來的計劃
for(pro in jh){
    document.write(pro,":",jh[pro],"<br>");
}
//沒有覆蓋address的值是成都市
for(pro in rs){
    document.write(pro,":",rs[pro],"<br>");
}
</script>