js验证密码必须为大小写字母和数字组成

<script language="JavaScript" type="text/JavaScript">

function checkPass(pass){

 if(pass.length < 6){  return 0; }

 var ls = 0;

 if(pass.match(/([a-z])+/)){  ls++; }  

 if(pass.match(/([0-9])+/)){  ls++; }  

 if(pass.match(/([A-Z])+/)){   ls++; }  

 if(pass.match(/[^a-zA-Z0-9]+/)){ ls++;}  

 return ls;

}  


function Validate(){

 var oldLogPWD = document.InfoForm.oldLogPWD;

 var newLogPWD = document.InfoForm.newLogPWD;

 var confirmLogPWD = document.InfoForm.confirmLogPWD;



 if(oldLogPWD.value.checkEmpty()){

   alert("旧登录密码不能为空!")

   oldLogPWD.focus();

   return false;

 }

if(newLogPWD.value.checkEmpty()){

  alert("新登录密码不能为空!")

  newLogPWD.focus();

  return false;

 }

if(checkPass(newLogPWD.value)<3){

  alert("新登录密码复杂度不够，请重新设置！");  

  newLogPWD.focus();  

  return false ;  

 }

if(newLogPWD.value!=confirmLogPWD.value){

  alert("确认新登录密码必须和新登录密码相等!");

  confirmLogPWD.focus();

  return false;

 }

if(newLogPWD.value==oldLogPWD.value){

    alert("新登录密码不可以与旧登录密码相等!");

    newLogPWD.focus();

    return false;

 }

 return true;

}



function SubmitForm(){

 if(Validate()){

 var con;

 con=confirm("请牢记您的密码,确认执行该操作吗？");

 if(con==true){

  document.InfoForm.submit();

  }

 }

}

</script>