function ds_getleft(el) {
	var tmp = el.offsetLeft;
	el = el.offsetParent
	while(el) {
		tmp += el.offsetLeft;
		el = el.offsetParent;
	}
	return tmp;
}

function ds_gettop(el) {
	var tmp = el.offsetTop;
	el = el.offsetParent
	while(el) {
		tmp += el.offsetTop;
		el = el.offsetParent;
	}
	return tmp;
}

showSubmenu = function(){
	subMenuObject = document.getElementById('subMenu');
	if (subMenuObject){
		subMenuObject.style.display="block";
	}
	HideOverSels(subMenuObject);
}


// JavaScript Document

// ���ر�IDΪobjID�Ķ��󣨲㣩�ڵ�������select
function HideOverSels(objID)
{
	var sels = document.getElementsByTagName('select'); 
    for (var i = 0; i < sels.length; i++) {
      if (Obj1OverObj2(objID, sels[i]))
        sels[i].style.visibility = 'hidden';     
	  else
		sels[i].style.visibility = 'visible';
	}
}

//�ж�obj1�Ƿ��ڵ���obj2
function Obj1OverObj2(obj1, obj2)
{
  var obj1Left = ds_getleft(obj1) ;
  var obj1Top = ds_gettop(obj1); 
  var obj1Right = obj1Left + obj1.offsetWidth; 
  var obj1Bottom = obj1Top + obj1.offsetHeight;
  var obj2Left = ds_getleft(obj2);
  var obj2Top = ds_gettop(obj2);
  var obj2Right = obj2Left + obj2.offsetWidth; 
  var obj2Bottom = obj2Top + obj2.offsetHeight;
  
  if (obj1Right <= obj2Left || obj1Bottom <= obj2Top || 
      obj1Left >= obj2Right || obj1Top >= obj2Bottom) {
    return false; 
  }else{
  	return true;
  }
}
function ShowOverSels()
{
	var sels = document.getElementsByTagName('select'); 
	for (var i = 0; i < sels.length; i++) {	
		sels[i].style.visibility = 'visible';
	}
}