密码强度验证

<script language="javascript" type="text/javascript">
//CharMode函数
//测试某个字符是属于哪一类.
function CharMode(iN){
if (iN>=48 && iN <=57) //数字
return 1;
if (iN>=65 && iN <=90) //大写字母
return 2;
if (iN>=97 && iN <=122) //小写
return 4;
else
return 8; //特殊字符
}
//bitTotal函数
//计算出当前密码当中一共有多少种模式
function bitTotal(num){
modes=0;
for (i=0;i<4;i++){
if (num & 1) modes++;
num>>>=1;
}
return modes;
}
//checkStrong函数
//返回密码的强度级别

function checkStrong(sPW){
if (sPW.length<=4)
return 0; //密码太短
Modes=0;
for (i=0;i<sPW.length;i++){
//测试每一个字符的类别并统计一共有多少种模式.
Modes|=CharMode(sPW.charCodeAt(i));
}
return bitTotal(Modes);
}

//pwStrength函数
//当用户放开键盘或密码输入框失去焦点时,根据不同的级别显示不同的颜色
function pwStrength(pwd){
O_color="#e0f0ff";
L_color="#FF0000";
M_color="#FF9900";
H_color="#33CC00";
if (pwd==null||pwd==''){
Lcolor=Mcolor=Hcolor=O_color;
}
else
{
S_level=checkStrong(pwd);
switch(S_level)
{
case 0:
Lcolor=Mcolor=Hcolor=O_color;
case 1:
Lcolor=L_color;
Mcolor=Hcolor=O_color;
break;
case 2:
Lcolor=Mcolor=M_color;
Hcolor=O_color;
break;
default:
Lcolor=Mcolor=Hcolor=H_color;
}
}

document.getElementById("strength_L").style.background=Lcolor;
document.getElementById("strength_M").style.background=Mcolor;
document.getElementById("strength_H").style.background=Hcolor;
return;
}

</script>

<form id="form1" runat="server">
<div>
输入密码:<asp:TextBox ID="TextBox1" runat="server" onKeyUp=pwStrength(this.value) onBlur=pwStrength(this.value) ></asp:TextBox><br />
密码强度:
<table border="1" cellpadding="1" borderColorDark="#fdfeff" borderColorLight="#99ccff" cellspacing="1" style="width: 200px; display: inline; background-color:#e0f0ff">
<tr>
<td id="strength_L" style="width: 100px; height: 19px;" align="center">
弱</td>
<td id="strength_M" style="width: 100px; height: 19px;" align="center">
中</td>
<td id="strength_H" style="width: 100px; height: 19px;" align="center">
强</td>
</tr>
</table>
</div>
</form>