rnd.today=new Date(); 
rnd.seed=rnd.today.getTime();

function rnd(){
    rnd.seed = (rnd.seed*9301+49297) % 233280;
    return rnd.seed/(233280.0);
}

function rand(number){
    return Math.ceil(rnd()*number);
}

function showAD(){
	var adm1 = document.getElementById("adm1");
	var adm2 = document.getElementById("adm2");

	var rnd1 = rand(2);

	if (rnd1==1) {
		adm1.style.display = "block";
	}else if (rnd1==2) {
		adm2.style.display = "block";
	}
}