function detectButtons()
{
    var elem = document.getElementById('content');
    var elemHeight = elem.offsetHeight;
    var logo = document.getElementById('logoButton');
    
    if (elemHeight > 480)
        logo.style.visibility = 'visible';

    is_topButtonNeeded();
    
    window.onresize = function (){
        is_topButtonNeeded();
    }
};

function browserSize(param)
{
  var myWidth = 0, myHeight = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    myWidth = window.innerWidth;
    myHeight = window.innerHeight;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    myWidth = document.documentElement.clientWidth;
    myHeight = document.documentElement.clientHeight;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    myWidth = document.body.clientWidth;
    myHeight = document.body.clientHeight;
  }
  return (param=="width") ? myWidth : myHeight;
}

function is_topButtonNeeded()
{
    winH = browserSize("height");
    var top = document.getElementById('topPageButton');
    var elem = document.getElementById('container');
    var elemHeight = elem.offsetHeight + 30;

    var setObjectTo = (elemHeight > winH) ? 'block' : 'none';

    top.style.display = setObjectTo;
};

initRouter_add(detectButtons);