function getHeader(){
var headers = new Array();
headers[0] = "1.png";
headers[1] = "2.png";
headers[2] = "3.png";


var i = Math.round(2*Math.random());

document.getElementById("header").style.backgroundImage= "url(http://sigfreds-kaffebar.dk/graphic/headers/" + headers[i] + ")";
}