function bilda() {
	var num=Math.floor(Math.random()*7)+1;
	document.writeln("<img src='/fileadmin/images/header/bild_a_"+num+".jpg' width='217' height='101'>");
	}

function bildb() {
	var num=Math.floor(Math.random()*7)+1;
	document.writeln("<img src='/fileadmin/images/header/bild_b_"+num+".jpg' width='217' height='101'>");
	}

function bildc() {
	var num=Math.floor(Math.random()*7)+1;
	document.writeln("<img src='/fileadmin/images/header/bild_c_"+num+".jpg' width='217' height='101'>");
	}