JavaScript 实现密码强度实时验证与前端展示

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>验证密码强度</title>
 <style type="text/css">
 *{margin: 0;padding: 0;}
 body{background:#ccc;}
 #demo{width:400px;padding:50px;background:#efefef;border: 1px solid #999;line-height:40px;margin:100px auto 0;}
 #strength_length{height:6px;width:100px;padding:2px;border: 1px solid #ccc;}
 .lv1{background:red;}
 .lv2{background:blue;width:200px;}
 .lv3{background:green;width:300px;}
 </style>
</head>
<body>
 <div id="demo">
 <label for="ipt">密码：</label>
 <input type="text" id="ipt"><br/>
 <em>密码强度：</em><em id="strength"></em>
 <div id="strength_length"></div>
 </div>
</body>
<script type="text/javascript">
 (function(window){
 function $(id){
 return document.getElementById(id);
 };
 var arr = ["","低","中","高"];
 // 获取对象
 var ipt = $("ipt"),strength = $("strength"),strLength = $("strength_length");
 // 密码输入事件
 ipt.onkeyup = function(){
 var s = 0;
 var txt = this.value;
 if( /[a-zA-Z]/.test(txt) ){
 s++;
 };
 if( /[0-9]/.test(txt) ){
 s++;
 };
 if( /[^0-9a-zA-Z]/.test(txt) ){
 s++;
 };
 if( txt.length <6 ){
 s = 0;
 };
 strength.innerHTML = arr[s];
 strLength.className = "lv" + s;
 }
 })(window)
</script>
</html>