javascript验证密码强度

function checkPassword(pwd){
   var objLow=document.getElementById("pwdLow");
   var objMed=document.getElementById("pwdMed");
   var objHi=document.getElementById("pwdHi");
  
   if(pwd.length<4){
     objLow.style.color="#ffffff";
     objMed.style.color = "";
     objHi.style.color = "";
   }else{
     var p1= (pwd.search(/[a-zA-Z]/)!=-1) ? 1 : 0;
     var p2= (pwd.search(/[0-9]/)!=-1) ? 1 : 0;
     var p3= (pwd.search(/[^A-Za-z0-9_]/)!=-1) ? 1 : 0;
     var pa=p1+p2+p3;
    
     if(pa==1){
       objLow.style.color="#ffffff";
     objMed.style.color = "";
     objHi.style.color = "";
     }else if(pa==2){
       objLow.style.color="";
     objMed.style.color = "#ffffff";
     objHi.style.color = "";
     }else if(pa==3){
       objLow.style.color="";
     objMed.style.color = "";
     objHi.style.color = "#ffffff";
     }
   }
 }