本节代码，用于判断密码的强度。
效果示例：
代码：
<html> <head> <title>JS判断密码强度--www.jb200.com</title> <script language=javascript> //判断输入密码的类型 function CharMode(iN){ if (iN>=48 && iN <=57) //数字 return 1; if (iN>=65 && iN <=90) //大写 return 2; if (iN>=97 && iN <=122) //小写 return 4; else return 8; } //bitTotal函数 //计算密码模式 function bitTotal(num){ modes=0; for (i=0;i<4;i++){ if (num & 1) modes++; num>>>=1; } return modes; } //返回强度级别 function checkStrong(sPW){ if (sPW.length<=4) return 0; //密码太短 Modes=0; for (i=0;i<sPW.length;i++){ //密码模式 Modes|=CharMode(sPW.charCodeAt(i)); } return bitTotal(Modes); } //显示颜色 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> </head> <body> <form name=form1 action="" > <table width="250" border="0" cellpadding=2" bordercolor="#eeeeee" style='display:inline'> <tr> <td width="40%" align="right">密码:</td> <td colspan="3" align="left"> <input type=password size=20 onKeyUp=pwStrength(this.value) onBlur=pwStrength(this.value)> </td> </tr> <tr align="center"> <td width="40%" align="right">密码强度:</td> <td width="20%" id="strength_L" bgcolor="#f5f5f5">弱</td> <td width="20%" id="strength_M" bgcolor="#f5f5f5">中</td> <td width="20%" id="strength_H" bgcolor="#f5f5f5">强</td> </tr> </table> </form> </body> </html>