检测密码强度

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>密码</title>
<style type="text/css">
body{
font-size:12px;
font-family: Arial, Helvetica, sans-serif;
margin:0;
}
form{
margin:2em;
}
#chkResult{margin-left:53px;height:15px;}
</style>
</head>

<body>
<script type="text/javascript" src="chkpwd.js"></script>
<form name="form1">
<label for="pwd">用户密码</label>
<input type="password" name="pwd" onKeyUp="chkpwd(this)" />
<div id="chkResult"></div>
<label for="pwd2">重复密码</label>
<input type="password" name="pwd2" />
</form>
<script type="text/javascript">
function chkpwd(obj){
var t=obj.value;
var id=getResult(t);

//定义对应的消息提示
var msg=new Array(4);
msg[0]="密码过短。";
msg[1]="密码强度差。";
msg[2]="密码强度良好。";
msg[3]="密码强度高。";

var sty=new Array(4);
sty[0]=-45;
sty[1]=-30;
sty[2]=-15;
sty[3]=0;

var col=new Array(4);
col[0]="gray";
col[1]="red";
col[2]="#ff6600";
col[3]="Green";

//设置显示效果
var bImg="http://bbs.blueidea.com/attachments/2006/12/7/pwdlen_dSIPeEGQWxfO.gif";//一张显示用的图片
var sWidth=300;
var sHeight=15;
var Bobj=document.getElementById("chkResult");

Bobj.style.fontSize="12px";
Bobj.style.color=col[id];
Bobj.style.width=sWidth + "px";
Bobj.style.height=sHeight + "px";
Bobj.style.lineHeight=sHeight + "px";
Bobj.style.background="url(" + bImg + ") no-repeat left " + sty[id] + "px";
Bobj.style.textIndent="20px";
Bobj.innerHTML="检测提示：" + msg[id];
}

//定义检测函数,返回0/1/2/3分别代表无效/差/一般/强
function getResult(s){
if(s.length < 4){
return 0;
}
var ls = 0;
if (s.match(/[a-z]/ig)){
ls++;
}
if (s.match(/[0-9]/ig)){
ls++;
}
if (s.match(/(.[^a-z0-9])/ig)){
ls++;
}
if (s.length < 6 && ls > 0){
ls--;
}
return ls
}
</script>
</body>

</html>