代码如下：
<!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> <label for="ipt">密码：</label> <input type="text"><br/> <em>密码强度：</em><em></em> <div></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>