<form name=form1 action="">输入密码:<input title="" 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"  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>

<script language=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;elsereturn 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) {var 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var 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) {var O_color = "#eeeeee";var L_color = "#FF0000";var M_color = "#FF9900";var 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;}
</script>