<script language=javascript>  //CharMode函数//source:www.web2bar.cn  //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="#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.getElementById("strength_L").style.background=Lcolor;  document.getElementById("strength_M").style.background=Mcolor;  document.getElementById("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>