function resize()
{

  var theWidth, theHeight;
  // Window dimensions:
  if (window.innerWidth) {
  theWidth=window.innerWidth;
  }
  else if (document.documentElement && document.documentElement.clientWidth) {
  theWidth=document.documentElement.clientWidth;
  }
  else if (document.body) {
  theWidth=document.body.clientWidth;
  }
  if (window.innerHeight) {
  theHeight=window.innerHeight;
  }
  else if (document.documentElement && document.documentElement.clientHeight) {
  theHeight=document.documentElement.clientHeight;
  }
  else if (document.body) {
  theHeight=document.body.clientHeight;
  }

  var main = document.getElementById("main");
  main.offsetHeight; 

  var header = document.getElementById("header");
  header.offsetHeight;

  var page = document.getElementById("page");
  page.offsetHeight;
 
  if(document.getElementById('footer'))
  {
    if(theHeight > page.offsetHeight)
    {
      if(theHeight > (header.offsetHeight + main.offsetHeight))
      {
        document.getElementById('footer').style.height=theHeight-(header.offsetHeight+main.offsetHeight-1) + 'px';
      }
      else alert(offsetHeight + main.offsetHeight);
    }
  }
}