var startbild = new Array() 

startbild[0] = 'bilder/bg2.jpg'
startbild[1] = 'bilder/bg3.jpg'

var j = 0
var p = startbild.length;
var preBuffer = new Array()
for (i = 0; i < p; i++)
	{
   		preBuffer[i] = new Image()
   		preBuffer[i].src = startbild[i]
	}
var whichImage = Math.round(Math.random()*(p-1));

function bw1 () 
		{
  document.write('<div id="container" style="background-image:url('+startbild[whichImage]+');">');
		}