var d=document;

function getXPos(obj)
{
  if(typeof(obj)=='string')
    {obj=d.getElementById(obj);}

  if(obj)
  {
    var curleft=0;
    if(obj.offsetParent)
    {
      while(obj.offsetParent)
      {
        curleft+=obj.offsetLeft
        obj=obj.offsetParent;
      }
    }
    else if (obj.x)
      curleft+=obj.x;
    return curleft;
  }
  else
    {return -1;}
}

function getYPos(obj)
{
  if(typeof(obj)=='string')
    {obj=d.getElementById(obj);}

  if(obj)
  {
    var curtop=0;
    if(obj.offsetParent)
    {
      while(obj.offsetParent)
      {
        curtop+=obj.offsetTop
        obj=obj.offsetParent;
      }
    }
    else if (obj.y)
      curtop+=obj.y;
    return curtop;
  }
  else
    {return -1;}
}

function getInnerWindowWidth()
{
  if (!window.innerWidth)
    {return d.documentElement.clientWidth;}
  else
    {return window.innerWidth;}
}

function getInnerWindowHeight()
{
  if(!window.innerHeight)
    {return d.documentElement.clientHeight;}
  else
    {return window.innerHeight;}
}

function windowCenterX()
{
  if(d.documentElement.scrollLeft>=0)
    {return getInnerWindowWidth()/2+d.documentElement.scrollLeft;}
  else
    {return getInnerWindowWidth()/2+window.pageXOffset;}
}

function windowCenterY()
{
  return getInnerWindowHeight()/2;
}

function pageScrollTop()
{
  if(d.documentElement.scrollTop>=0)
    {return d.documentElement.scrollTop;}
  else
    {return window.pageYOffset;}
}