function newImage(arg) {
	    if (document.images) {
		    rslt = new Image();
		    rslt.src = arg;
		    return rslt;
	    }
    }
     
    function preloadImages() {
	    if (document.images) {
		    var headerShadow = newImage("images/header_shadow.jpg");
		}
    }

    preloadImages();

    function setHeader (){
      var Header = document.getElementById("header");
      var HeaderShadow = document.getElementById("header_shadow");
      

      var l;

      if (Header) {
      
      var w=document.body.offsetWidth;
      var oh = document.body.scrollTop;
        
      if (w>=800) {
        l=(w-800)/2;
      }
      else {
        l=0;
      }
      Header.style.position = "absolute";
      Header.style.left=l.toString() + "px";
      Header.style.top= (oh-1).toString() + "px";
      Header.style.visibility = "visible";
      
      HeaderShadow.style.position = "absolute";
      HeaderShadow.style.left=(l-3).toString() + "px";
      HeaderShadow.style.top= (oh-4).toString() + "px";
      HeaderShadow.style.visibility = "visible";
      }
  }

  function setFooter (){

    
      var footer = document.getElementById("footer");

      var l;

      if (footer) {
        var w=document.body.offsetWidth;
        var h=document.body.offsetHeight -17;
        var oh = document.body.scrollTop;
        
          if (w>=800) {
            l=(w-800)/2;
          }
          else {
            l=0;
          }
          footer.style.position = "absolute";
            
          footer.style.left=l.toString() + "px";
          footer.style.top=(h + oh -1).toString() + "px";
          if (footer.style.visibility != "visible") {
            footer.style.visibility = "visible";
          }
      }
  }
  
  function doBoth() {
    setHeader();
    setFooter();
  }
    
  window.onload= doBoth;
  window.onresize = doBoth;
  window.onscroll = doBoth;