function fade(id,InOut){// 淡入淡出函式
		var dur=40;// 淡入淡出步數
		var txt=document.getElementById(id);

		var opacity=0,sTimer = setInterval(function(){
			if(opacity != dur){
			  set_opacity = (InOut=="in")?opacity*(100/dur):100 - opacity*(100/dur);
			  txt.style.filter = "alpha(opacity:"+set_opacity+")";// IE/Win
			  txt.style.KHTMLOpacity = set_opacity/100;// Safari<1.2, Konqueror
			  txt.style.MozOpacity = set_opacity/100;// Older Mozilla and Firefox
			  txt.style.opacity = set_opacity/100;// Safari 1.2, newer Firefox and Mozilla, CSS3
			}else{
				clearInterval(sTimer);
				div_disappear(id);
			}
			opacity++;
		},50);

	}

function div_disappear(id){ //漸漸消失

	var obj_nav=document.getElementById(id);
	obj_nav.style.overflow="hidden";
	if(obj_nav.style.width==""){
		obj_nav.style.width="100%";
	}
	var H=obj_nav.clientHeight;
	var n=20,t=50;
	var timers=new Array(n);
    for(var i=0;i<n;i++){(
     function(){
      var j=i;
      timers[i]=setTimeout(function(){
	   now_height = H-Math.round(H*(j+1)/n);
       obj_nav.style.height=now_height+"px";
	   if(now_height<=0){obj_nav.style.display="none";}
       },(i+1)*t);
     }
    )()};
}