addLoadListener(checkFooterMenuVisibility);
addResizeListener(checkFooterMenuVisibility);

function checkFooterMenuVisibility()
{
    // IF THE CONTENTBOX IS HIGHER THAN THE VIEWPORT WE SHOULD MAKE IT VISIBLE, ELSE WE HIDE IT
    var contentheight = $('content').getHeight();
    var viewportheight = getViewportSize()[1];
    if (contentheight > viewportheight)
    {
        $('footermenu').setStyle({visibility: 'visible'});
    }
    else
    {
        $('footermenu').setStyle({visibility: 'hidden'});
    }
}




function getViewportSize()
{
  var size = [0, 0];

  if (typeof window.innerWidth != 'undefined')
  {
    size = [
        window.innerWidth,
        window.innerHeight
    ];
  }
  else if (typeof document.documentElement != 'undefined'
      && typeof document.documentElement.clientWidth != 'undefined'
      && document.documentElement.clientWidth != 0)
  {
    size = [
        document.documentElement.clientWidth,
        document.documentElement.clientHeight
    ];
  }
  else
  {
    size = [
        document.getElementsByTagName('body')[0].clientWidth,
        document.getElementsByTagName('body')[0].clientHeight
    ];
  }

  return size;
}

function addLoadListener(fn)
{
    if (typeof window.addEventListener != 'undefined')
    {
        window.addEventListener('load', fn, false);
    }
    else if (typeof document.addEventListener != 'undefined')
    {
        document.addEventListener('load', fn, false);
    }
    else if (typeof window.attachEvent != 'undefined')
    {
        window.attachEvent('onload', fn);
    }
    else
    {
        var oldfn = window.onload;
        if (typeof window.onload != 'function')
        {
            window.onload = fn;
        }
        else
        {
            window.onload = function()
            {
                oldfn();
                fn();
            };
        }
    }
}

function addResizeListener(fn)
{
    if (typeof window.addEventListener != 'undefined')
    {
        window.addEventListener('resize', fn, false);
    }
    else if (typeof document.addEventListener != 'undefined')
    {
        document.addEventListener('resize', fn, false);
    }
    else if (typeof window.attachEvent != 'undefined')
    {
        window.attachEvent('onresize', fn);
    }
    else
    {
        var oldfn = window.onresize;
        if (typeof window.onresize != 'function')
        {
            window.onresize = fn;
        }
        else
        {
            window.onresize = function()
            {
                oldfn();
                fn();
            };
        }
    }
}