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jsLab.html
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<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>JS实验室</title>
<script type="text/javascript">
function people( name) {
this.name = name;
}
people.prototype.bind = function(oThis) { // 实参还会有很多，oThis只是需要绑定的必须参数
if (!Function.prototype.bind) {
if (typeof this !== 'function') { // 这里的this是调用bind函数的那个对象
throw new TypeError("Function.prototype.bind - what is tring" + "to be bound is not callable");
}
var aArgs = [].slice.call(arguments, 1); // 保存除需要绑定this之外的参数
var fnToBind = this;
var fnNOP = function() {}; // 临时中转函数，防止继承函数的prototye改变，被继承函数的prototye也被改变
var fnBound = function() {
return fnToBind.apply(
// 判断硬绑定函数是否是被 new 调用，如果是的话就会使用新创建的 this 替换赢绑定的this
(this instanceof fnNOP && oThis ? this : oThis), // new修改this的代码1
aArgs.concat([].slice.call(arguments)));
};
fnNOP.prototype = this.prototype; // new修改this的代码2
fnBound.prototype = new FnNOP();
// fnBound.prototype = Object.create(fnToBind.prototype);
return fnBound;
}
};
var a = {};
var b = people.bind(a);
b('xby');
console.log(a.name); // xby
var c = new b('cm');
console.log(c.name); // cm
console.log(a.name); // xby
</script>
</head>
<body>
<p>开始神奇的JS之旅，立志成为JS Ninja</p>
</body>
</html>