maxc = 3;
function showChild(sel){
	frm = sel.form;
	n = sel.options[sel.selectedIndex].value;
	hideAll(frm);
	for(i=1;i<=n;i++){
		frm["num_"+i].style.display="inline";
	}	
}
function hideAll(frm){
	for(i=1;i<=maxc;i++){
		frm["num_"+i].style.display="none";
	}
}