var viewportwidth;
var viewportheight;
    
function adjustScroll(_height)	{
    howTall();
    if(viewportheight == null || viewportheight >  _height)	{
        //document.body.style.overflow = "hidden";
    }
    else	{
        //document.body.style.overflow = "scroll";
    }
}
function howTall() { 
    
     
     // the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
     
     if (typeof window.innerWidth != 'undefined')
     {
          viewportwidth = window.innerWidth,
          viewportheight = window.innerHeight
     }
     
    // IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
    
     else if (typeof document.documentElement != 'undefined'
         && typeof document.documentElement.clientWidth !=
         'undefined' && document.documentElement.clientWidth != 0)
     {
           viewportwidth = document.documentElement.clientWidth,
           viewportheight = document.documentElement.clientHeight
     }
     
     // older versions of IE
     
     else
     {
           viewportwidth = document.getElementsByTagName('body')[0].clientWidth,
           viewportheight = document.getElementsByTagName('body')[0].clientHeight
     }
}