javascript面向对象之对象的深入理解

<script language="javascript" type="text/javascript">
function Cat(){
}

var cat1 = new Cat();//创建类实例

cat1.name = "小狗";
cat1.age = 4;
cat1.color="白色";
document.write(cat1.name);

document.writeln(cat1.constructor);//实例化后对象，是对象
document.writeln(typeof(cat1)+"<hr />");

document.writeln(Cat.constructor);//原型对象本身也是对象
document.writeln(typeof Cat+"<hr />");

var b="hello";//字符串也是对象
document.writeln(b.constructor);//输出它的构造函数
document.writeln(typeof b+"<hr />");

var c=123;//数值也是对象
document.writeln(c.constructor);
document.writeln(typeof c+"<hr />");
</script>

if(cat1 instanceof Cat){//与php的判断方法相同
 window.alert("ok");
}