function $C(element, parent) { 
	elem = document.createElement(element);
	
	if (typeof(parent) != "undefined") {
		parent.appendChild(elem);
	}
	
	return elem; 
}

function $CT(text, parent) { 
	textnode = document.createTextNode(text);
	
	if (typeof(parent) != "undefined") {
		parent.appendChild(textnode);
	}
	
	return textnode; 
}

function $px(number) {
	return number + "px";
}

function $unpx(text) {
	if (text.substr(text.length - 2, 2) != "px") return text;
	return parseInt(text.substr(0, text.length - 2));
}

function $id(prefix, nr) {
	return prefix + nr;
}

function $unid(prefix, id) {
	if (typeof(prefix) == "undefined") return id;
	if (prefix == null) return id;
	if (prefix.length == 0) return id;
	if (id.startsWith(prefix)) return id.substr(prefix.length);
	return id;
}