密码强度检测

<script type="text/javascript">
var $ = function(v){return document.getElementById(v);}
function isSecurity(v){
 if (v.length < 3) { iss.reset();return;}
 var lv = -1;
 if (v.match(/[a-z]/ig)){lv++;}
 if (v.match(/[0-9]/ig)){lv++;}
 if (v.match(/(.[^a-z0-9])/ig)){lv++;}
 if (v.length < 6 && lv > 0){lv--;}
 iss.reset();
 switch(lv) {
 case 0:
 iss.level0();
 break;
 case 1:
 iss.level1();
 break;
 case 2:
 iss.level2();
 break;
 default:
 iss.reset();
 }
}
var iss = {
 color:["CC0000","FFCC33","66CC00","CCCCCC"],
 text:["弱","中","强"],
 width:["50","100","150","10"],
 reset:function(){
 $("B").style.backgroundColor = iss.color[3];
 $("B").style.width = iss.width[3];
 $("A").innerHTML = "验证试中";
 },
 level0:function(){
 $("B").style.backgroundColor = iss.color[0];
 $("B").style.width = iss.width[0];
 $("A").innerHTML = "较弱";
 },
 level1:function(){
 $("B").style.backgroundColor = iss.color[1];
 $("B").style.width = iss.width[1];
 $("A").innerHTML = "中";
 },
 level2:function(){
 $("B").style.backgroundColor = iss.color[2];
 $("B").style.width = iss.width[2];
 $("A").innerHTML = "高强";
 }
}
</script>
<input type="password" name="password" size="25" maxlength="20" onkeyup="isSecurity(this.value);">
<font class="red" id="A">密码强度</font>
<table height="8" border="1" align="left" cellpadding="0" cellspacing="0" bordercolor="#EEEEEE" style="border-collapse:collapse;">
<tr>
 <td bgcolor="#EEEEEE" width="1" align="center" valign="middle" id="B"></td>
</tr>
</table>