var moveing = false;
function $(id) { return document.getElementById(id); }
function moveElement(elementID,final_x,final_y,interval) {
  if (!document.getElementById) return false;
  if (!document.getElementById(elementID)) return false;
  var elem = document.getElementById(elementID);
  if (elem.movement) {
    clearTimeout(elem.movement);
  }
  if (!elem.style.left) {
    elem.style.left = "0px";
  }
  if (!elem.style.top) {
    elem.style.top = "0px";
  }
  var xpos = parseInt(elem.style.left);
  var ypos = parseInt(elem.style.top);
  if (xpos == final_x) {
	moveing=false;
    return true;
  }
  if (xpos < final_x) {
    var dist = Math.ceil((final_x - xpos)/10);//Math.ceil求最小的整数，但不小于本身
    xpos = xpos + dist;
  }
  if (xpos > final_x) {
    var dist = Math.ceil((xpos - final_x)/10);
    xpos = xpos - dist;
  }
  if (ypos < final_y) {
    var dist = Math.ceil((final_y - ypos)/10);
    ypos = ypos + dist;
  }
  if (ypos > final_y) {
    var dist = Math.ceil((ypos - final_y)/10);
    ypos = ypos - dist;
  }
  elem.style.left = xpos + "px";
  elem.style.top = ypos + "px";
  var repeat = "moveElement('"+elementID+"',"+final_x+","+final_y+","+interval+")";
  elem.movement = setTimeout(repeat,interval);
}
function next(previousBtn,nextBtn,scrollID) {
	
	if(moveing) return;
	moveing = true;
	var vTop = parseInt($(scrollID).style.top);
	var vLeft = parseInt($(scrollID).style.left);
	if (vLeft <= -1660) {//return moveing=false;
		$(scrollID).style.left = 0 + "px";
		vLeft = 0;
	}
	
	var finalLeft = vLeft - 166;
	moveElement(scrollID,finalLeft,vTop,5);
	
	
	
}
function previous(previousBtn,nextBtn,scrollID) {
	if(moveing) return;
	moveing = true;
	var vTop = parseInt($(scrollID).style.top);
	var vLeft = parseInt($(scrollID).style.left);
	if (vLeft >= 0) { //return moveing=false;
		$(scrollID).style.left = -1660 + "px";
		vLeft = -1660;
	}
	var finalLeft = vLeft + 166;
	moveElement(scrollID,finalLeft,vTop,5);
	
}