//获得obj的绝对位置x
function getObjLeft(obj)
{
	//var obj = document.getElementById(id);
  var eleft = obj.offsetLeft;
	
  while (obj = obj.offsetParent){
    eleft += obj.offsetLeft;
	}
	return eleft;
}

//获得obj的绝对位置y
function getObjTop(obj)
{
	//var obj = document.getElementById(id);
  var etop = obj.offsetTop;
	
  while (obj = obj.offsetParent){
    etop+=obj.offsetTop;
	}
	return etop; 
}

//定位
function setPosition(obj1,obj2,top,left){
	var etop  = getObjTop(obj1);
	var eleft = getObjLeft(obj1);
	var eeleft = document.body.clientWidth - 200 + document.body.scrollLeft;
	if (eleft > eeleft){
		eleft =  eeleft - left;
	}   
	obj2.style.top  = etop+top;
	obj2.style.left = eleft;
}

function MM_Show(id,idpo,top,left)
{
  var obj = document.getElementById(id);
  var objpo = document.getElementById(idpo);
  obj.style.visibility="visible";
  setPosition(objpo,obj,top,left);
}

function MM_Hide(id)
{
  var obj = document.getElementById(id);
  obj.style.visibility="hidden";
}