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";
}
}
}