javascript面向对象之this关键词用法分析

<script language="javascript" type="text/javascript">
function Person(){
 this.name = "王美人";
 this.age = 25;
};
var p1 = new Person();
var p2 = new Person();

document.writeln(p1.name+"<br />");
document.writeln(p2.name);
</script>

<script language="javascript" type="text/javascript">
var name="北京";
window.alert(this.name);//输出“北京”
</script>