function checkNumPages() {
	var gameControl = document.getElementsByName("level_game").item(0);
	var pageControl = document.getElementsByName("level_page").item(0);
	var numLevels = Math.ceil(gameLevels[gameControl.selectedIndex] / 10);
	var pageControlLength = pageControl.length;
	
	if(numLevels < pageControlLength) { // Remove pages
		for(var i = numLevels; i < pageControlLength; i++) {
			pageControl.remove(numLevels);
		}
	} else if(numLevels > pageControlLength) { // Add pages
		for(var i = pageControlLength + 1; i <= numLevels; i++) {
			var option = document.createElement("option");
			option.value = i;
			option.innerHTML = i;
			pageControl.add(option, null);
		}
	}
}

function checkSortType() {
	var sort = document.getElementsByName("level_sort").item(0).value;
	var gameControl = document.getElementsByName("level_game").item(0);
	var pageControl = document.getElementsByName("level_page").item(0);
	
	if(sort == "featured") {
		gameControl.disabled = true;
		pageControl.disabled = true;
	} else {
		gameControl.disabled = false;
		pageControl.disabled = false;
		checkNumPages();
	}
}

function filterLevels() {
	var sort = document.getElementsByName("level_sort").item(0).value;
	var game = document.getElementsByName("level_game").item(0).value;
	var page = document.getElementsByName("level_page").item(0).value;
	
	if(window.location.pathname != "/content.php")
		window.location.pathname = "/content.php";
	window.location.search = "module=levels&sort=" + sort + (sort == "featured"? "" : "&game=" + game + "&page=" + page);
}