var now = new Date();
var theday = now.getDate()-1;
var themonth = now.getMonth();
var theyear = now.getFullYear();

function setDrops(theForm) {
theForm.day.selectedIndex = theday;
theForm.month.selectedIndex = themonth;

var found = 0;
for(i=1;i<theForm.year.options.length;i++) {
if (theForm.year.options[i].value == theyear) {
found = i;
break;
}
}
theForm.year.selectedIndex = found;
}