var hdrs = 39;

function randHeader() {
	var rand = (Math.random() * hdrs);
	rand = Math.round(rand);
	id = document.getElementById("header");
	var tmp = "header" + rand;
	id.className = tmp;
}

function headerShift(num) {
	id = document.getElementById("header");
	var tmp = "header" + num;
	id.className = tmp;
}