function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			oldonload();
			func();
		};
	}
}

function $$$ (id){
	return document.getElementById(id);
}

function dynamicoptions(num) {
	if($$$('roomnumber').options.length < num){
		for(var i = $$$('roomnumber').options.length; i < num; i++) {
			$$$('roomnumber').options[i] = new Option((i+1),(i+1));
		}
	}
	if($$$('roomnumber').options.length > num){
		for(var j = ($$$('roomnumber').options.length-1); j > (num-1); j--) {
			$$$('roomnumber').options[j] = null;
		}
	}
	return false;
}

function dynamicroom () {
	//var mas = [4,3,1,4];
	var mas = [3,1,4,1,4,1];
	dynamicoptions(mas[$$$('room').options.selectedIndex]);
}

function addevent() {
	if(typeof document.addEventListener !== 'undefined') {
		$$$('room').addEventListener('change', dynamicroom, false );
	}
	else if(document.attachEvent !== 'undefined') {
		$$$('room').attachEvent('onchange', dynamicroom);
	}
}

addLoadEvent(addevent);
addLoadEvent(dynamicroom);