js模拟jq获取id：
（jquery）需要自己添加
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>js模拟jq的点击效果</title>
<style>
* {margin: 0; padding: 0;}
#btn {display:block;height: 30px; 100px;margin: 100px auto 0;}
</style>
</head>
<body>
<button id="btn">点击</button>
<script>
(function(){
function $(targetID) {
var word = targetID.substring(0,1);
if (word == '#') {
var ID = targetID.replace(/#/g,'');
var obj = document.getElementById(ID);
obj.click = function(fn) {
this.onclick = fn;
}
return obj;
}
}
window.jQuery = $;
window.$ = window.jQuery;
})();
$('#btn').click(function() {
alert('qqq');
});
</script>
</body>
</html>