js对象都有constructor属性，但是构造函数产生的对象和简单对象的属性有些不同，可自行运行以下代码了解
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf⑻" />
<title>对象上的特殊属性</title>
</head>
<body>
<script type="text/javascript">
function Hero(name) {
this.name = name;
this.occupation = 'Ninja';
this.whoAreYou = function() {
return "I'm " + this.name + " and I'm a " + this.occupation;
}
}
var h1 = new Hero('Michelangelo');
alert(h1.constructor);//返回1个函数
var obj = {};//var obj = new Object();
alert(obj.constructor);
</script>
</body>
</html>