js检测用户输入密码强度

<input name="password" type="PassWord" onKeyUp="CheckIntensity(this.value)"> 
<table border="0" cellpadding="0" cellspacing="0"> 
 <tr align="center"> 
 <td id="pwd_Weak" class="pwd pwd_c">&nbsp;</td> 
 <td id="pwd_Medium" class="pwd pwd_c pwd_f">无</td> 
 <td id="pwd_Strong" class="pwd pwd_c pwd_c_r">&nbsp;</td> 
 </tr> 
</table> 

.pwd{width:40px;height:20px;line-height:14px;padding-:2px;} 
.pwd_f{color:#BBBBBB;} 
.pwd_c{background-color:#F3F3F3;border-:1px solid #D0D0D0;border-bottom:1px solid #D0D0D0;border-left:1px solid #D0D0D0;} 
.pwd_Weak_c{background-color:#FF4545;border-:1px solid #BB2B2B;border-bottom:1px solid #BB2B2B;border-left:1px solid #BB2B2B;} 
.pwd_Medium_c{background-color:#FFD35E;border-:1px solid #E9AE10;border-bottom:1px solid #E9AE10;border-left:1px solid #E9AE10;} 
.pwd_Strong_c{background-color:#3ABB1C;border-:1px solid #267A12;border-bottom:1px solid #267A12;border-left:1px solid #267A12;} 
.pwd_c_r{border-right:1px solid #D0D0D0;} 
.pwd_Weak_c_r{border-right:1px solid #BB2B2B;} 
.pwd_Medium_c_r{border-right:1px solid #E9AE10;} 
.pwd_Strong_c_r{border-right:1px solid #267A12;} 

function CheckIntensity(pwd){ 
 var Mcolor,Wcolor,Scolor,Color_Html; 
 var m=0; 
 var Modes=0; 
 for(i=0; i<pwd.length; i++){ 
 var charType=0; 
 var t=pwd.charCodeAt(i); 
 if(t>=48 && t <=57){charType=1;} 
 else if(t>=65 && t <=90){charType=2;} 
 else if(t>=97 && t <=122){charType=4;} 
 else{charType=4;} 
 Modes |= charType; 
 } 
 for(i=0;i<4;i++){ 
 if(Modes & 1){m++;} 
  Modes>>>=1; 
 } 
 if(pwd.length<=4){m=1;} 
 if(pwd.length<=0){m=0;} 
 switch(m){ 
 case 1 : 
  Wcolor="pwd pwd_Weak_c"; 
  Mcolor="pwd pwd_c"; 
  Scolor="pwd pwd_c pwd_c_r"; 
  Color_Html="弱"; 
 break; 
 case 2 : 
  Wcolor="pwd pwd_Medium_c"; 
  Mcolor="pwd pwd_Medium_c"; 
  Scolor="pwd pwd_c pwd_c_r"; 
  Color_Html="中"; 
 break; 
 case 3 : 
  Wcolor="pwd pwd_Strong_c"; 
  Mcolor="pwd pwd_Strong_c"; 
  Scolor="pwd pwd_Strong_c pwd_Strong_c_r"; 
  Color_Html="强"; 
 break; 
 default : 
  Wcolor="pwd pwd_c"; 
  Mcolor="pwd pwd_c pwd_f"; 
  Scolor="pwd pwd_c pwd_c_r"; 
  Color_Html="无"; 
 break; 
 } 
 document.getElementById('pwd_Weak').className=Wcolor; 
 document.getElementById('pwd_Medium').className=Mcolor; 
 document.getElementById('pwd_Strong').className=Scolor; 
 document.getElementById('pwd_Medium').innerHTML=Color_Html; 
}