function chkpwd(obj){
		var t=obj.value;
		var id=getResult(t);
		
/*		var msg=new Array(4);
		msg[0]="useless";
		msg[1]="bad";
		msg[2]="normal";
		msg[3]="good";
*/		
		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";
		
		//set show effect.
		var bImg="/blog/pictures/notice.gif";//pic
		var sWidth=300;
		var sHeight=15;
		var Bobj=document.getElementById("chkResult");

		Bobj.style.fontSize="12px";
		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=notice+msg[id];
	}
	
	//return 0/1/2/3 means useless/bad/normal/good.
	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
	}