<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>关于hasOwnProperty()方法的应用</title>
</head>
<body>
<script>
if (typeof Object.prototype.clone === "undefined") {
Object.prototype.clone = function () {
alert(this.b)
};
}
var a ={b:1}
a.clone()
</script>
</body>
</html>