function check(form) {
	form.topic.style.background="#ffffff";
	form.url.style.background="#ffffff";
	form.post_content.style.background="#ffffff";
	
	if (form.topic.value == "") {
		alert("Een titel is verplicht.");
		form.topic.style.background="#f138aa";
		form.topic.focus();
		return false;
	}
	else if (form.url.value == "" || form.url.value == "http://") {
		alert("Een URL is verplicht.");
		form.url.style.background="#f138aa";
		form.url.focus();
		return false;
	} 
	else if (form.post_content.value == "") {
		alert("Een beschrijving is verplicht.");
		form.post_content.style.background="#f138aa";
		form.post_content.focus();
		return false;
	} 
	else
		return true;	
}

function check_video(form) {
	form.topic.style.background="#ffffff";
	form.post_html.style.background="#ffffff";
	form.post_content.style.background="#ffffff";
	
	if (form.topic.value == "") {
		alert("Een titel is verplicht.");
		form.topic.style.background="#f138aa";
		form.topic.focus();
		return false;
	}
	else if (form.post_html.value == "") {
		alert("De HTML code voor de video is verplicht.");
		form.post_html.style.background="#f138aa";
		form.post_html.focus();
		return false;
	} 
	else if (form.post_content.value == "") {
		alert("Een beschrijving is verplicht.");
		form.post_content.style.background="#f138aa";
		form.post_content.focus();
		return false;
	} 
	else
		return true;	
}