var theImages = new Array();
theImages[0] = 'header1';
theImages[1] = 'header2';
theImages[2] = 'header3';
theImages[3] = 'header4';
var j = 0;
var p = theImages.length;

var preBuffer = new Array();

for (i = 0; i < p; i++) {
   preBuffer[i] = new Image();
   preBuffer[i].src = theImages[i];
}

var whichImage = Math.round(Math.random()*(p-1));

function showImage() {
	document.write('<img src="/images/'+theImages[whichImage]+'" alt="KAASPACK" border="0"/>');
}
function showBackground(item_id){
  $(item_id).className = theImages[whichImage];
}