相关知识点：
构造函数、原型对象、实例对象
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
.wrap {
margin: 50px;
200px;
height: 200px;
border: 1px solid red;
}
.active {
border-color: yellow;
}
</style>
</head>
<body>
<div class="wrap" data-html="hello"></div>
<script>
function $(s) {
return document.querySelector(s);
}
function attr(obj, data) {
return obj.getAttribute(data);
}
function ChangeEle(obj) {
this.ele = obj;
this.ele.dataHtml = attr(this.ele, 'data-html');
}
ChangeEle.prototype.myHtml = function () {
var ele=this.ele;
ele.innerHTML = ele.dataHtml;
}
ChangeEle.prototype.replaceStr = function (str) {
var ele=this.ele;
ele.innerHTML = ele.innerHTML === ele.dataHtml ? str : ele.dataHtml;
}
ChangeEle.prototype.addEvent = function (type, fn) {
this.ele.addEventListener(type, fn);
}
var myWrap = new ChangeEle($('.wrap'));
myWrap.myHtml();
myWrap.addEvent('click', function () {
myWrap.replaceStr('world');
});
</script>
</body>
</html>