简单模仿jquery的几个特性

使用了jquery之后，原生的javascript写的很少了，最近准备复习下，于是想到了自己写一点js来模拟jquery的几个核心特性。

先看页面代码：

页面效果是点击超链接后设置三个p标签中的内容，然后添加一个css class使背景变成灰色，但并没有用到jquery库。

再来看下我的js代码（jquery-learn.js)：

做了什么：

1.注册文档加载完成的事件处理程序；

　　$()函数中判断参数是否是一个函数，如果是就将该函数注册给window.onload时间。
2.id、class选择器；

　　利用document.getElementById和document.getElementByClassName函数实现。
3.click事件绑定函数；

　　分别给匹配的每一个dom元素绑定onclick事件。
4.text函数获取元素文本；

　　获取第一个（或设置所有）匹配元素的innerText属性。
5.html函数设置元素html内容；

　　获取或设置所有匹配元素的innerHTML属性。
6.addClass函数为元素添加css class；

　　向所有匹配元素中添加一个class。
7.链式操作；

　　jquery对象的方法最后返回this，函数式编程：$("").html("").addClass("")。
8.隐式迭代

　　默认的将操作作用在匹配的所有元素上，关键在于jquery对象中有一个存储dom对象的数组：domELes。

 

说明：jquery的强大真的可以让我们写很少的代码来实现需要的效果，但不要用了jquery忘了javascript。

当然这里的简单实现目的只是为了展示jquery的几个特性的大致实现原理，代码当中也有很多不妥之处，这里也没有模拟jquery的dom操作、动画、浏览器兼容、Ajax等重要特性。

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