var ok_obj=document.getelementbyid("view_pic").getelementsbytagname("li");
var ok=math.ceil(ok_obj.length/3)-1;
var ele=document.getelementbyid("description");
var w=ele.clientwidth / 4;
var n=20,t=50;
var timers=new array(n);
var k=0;

doslide(0);

function doslide(s){
  if (k>=ok &&s>0|| k<=0 &&s<0)menuclick()
 else{
  k+=s;
    var x=ele.scrollleft;
    var d=k*w-x;
    for(var i=0;i<n;i++)(
    	function(){
    		if(timers[i]) cleartimeout(timers[i]);
    		var j=i;
//    		alert(x)
    		timers[i]=settimeout(function(){ele.scrollleft=x+math.round(d*math.sin(math.pi*(j+1)/(2*n)));},(i+1)*t);
    	}
    )();
}}

var intdelay=30; //设置菜单显示速度，越大越慢
var intinterval=5;