// JavaScript Document

function zufallszahl(n){ 
	zahl = Math.floor(Math.random()* (n+1)); 
	return zahl; 
} 

var cssklasse = new Array(); 
cssklasse[0] = "banner_pic1" ; 
cssklasse[1] = "banner_pic2" ; 
cssklasse[2] = "banner_pic3" ; 
cssklasse[3] = "banner_pic4" ;

function wechseln(){ 
	var target = document.getElementById("banner"); 
	target.className = cssklasse[zufallszahl(cssklasse.length - 1)]; 
}