用Javascript评估用户输入密码的强度实现代码

<script language="javascript">
//CharMode函数 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 function bitTotal(num){
modes=0;
for (i=0;i<4;i++){
if (num & 1) modes++;
num>>>=1; return modes; //checkStrong函数 function checkStrong(sPW){
if (sPW.length<=4)
return 0; //密码太短
Modes=0;
for (i=0;i<sPW.length;i++){ Modes|=CharMode(sPW.charCodeAt(i)); return bitTotal(Modes); //pwStrength函数 function pwStrength(pwd){
O_color="#eeeeee";
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.getElementByIdx_x("strength_L").style.background=Lcolor;
document.getElementByIdx_x("strength_M").style.background=Mcolor;
document.getElementByIdx_x("strength_H").style.background=Hcolor;
return; </script>
<form name=form1 action="" >
输入密码:<input type="password" size="10" onKeyUp="pwStrength(this.value)" onBlur="pwStrength(this.value)">
<br>密码强度:
<table width="217" border="1" cellspacing="0" cellpadding="1"
bordercolor="#cccccc" height="23" style='display:inline'>
<tr align="center" bgcolor="#eeeeee">
<td width="33%" id="strength_L">弱</td>
<td width="33%" id="strength_M">中</td>
<td width="33%" id="strength_H">强</td>
</tr>
</table>
</form>