function chkpwd(obj){
        var t=obj.value;
        var id=getResult(t);
        
        //定义对应的消息提示
        var msg=new Array(4);
        msg[0]="密码过短。";
        msg[1]="密码强度差。";
        msg[2]="密码强度良好。";
        msg[3]="密码强度高。";
        
        var sty=new Array(4);
        sty[0]=-45;
        sty[1]=-30;
        sty[2]=-15;
        sty[3]=0;
        
        var col=new Array(4);
        col[0]="gray";
        col[1]="red";
        col[2]="#ff6600";
        col[3]="Green";
        
        //设置显示效果
        var bImg="attachments/month_0612/v200612702136.gif";//一张显示用的图片
        var sWidth=300;
        var sHeight=15;
        var Bobj=document.getElementById("chkResult");

        Bobj.style.fontSize="14px";
        Bobj.style.color=col[id];
        Bobj.style.width=sWidth + "px";
        Bobj.style.height=sHeight + "px";
        Bobj.style.lineHeight=sHeight + "px";
        Bobj.style.background="url(" + bImg + ") no-repeat left " + sty[id] + "px";
        Bobj.style.textIndent="20px";
        Bobj.innerHTML="检测提示：" + msg[id];
    }
    
    //定义检测函数,返回0/1/2/3分别代表无效/差/一般/强
    function getResult(s){
        if(s.length < 4){
            return 0;
        }
        var ls = 0;
        if (s.match(/[a-z]/ig)){
            ls++;
        }
        if (s.match(/[0-9]/ig)){
            ls++;
        }
         if (s.match(/(.[^a-z0-9])/ig)){
            ls++;
        }
        if (s.length < 6 && ls > 0){
            ls--;
        }
        return ls
    }