var total = 2; 	
var aleatorio = Math.random();
var valor = 1/total;
var achou = false;
var indice = 0;
for (var i=0; i<total && !achou; i++) {
        if (aleatorio>i*valor && aleatorio<=(i+1)*valor) {
                indice = i;
                achou = true;
        }
}
if(i == 1) {
document.write('<a href="agendadanada.htm#cervejada"><img src="images/cervejada3.gif" width="766" height="90" alt="" border="0"></a>')
}
if(i == 2) {
document.write('<a href="agendadanada.htm#cervejada"><img src="images/cervejada3.gif" width="766" height="90" alt="" border="0"></a>')
}