function c (nombre) {
	return document.createElement(nombre);
}

function i (nombre) {
	return document.getElementById(nombre);
}

function d (id, x, y, w, h, bg, pos, f) {
	var bg  = bg  || "grey";
	var pos = pos || "absolute";
	var f   = f   || "left";
	var div = c("div");
	div.style.left = x;
	div.style.top = y;
	div.style.backgroundColor = bg;
	div.style.position = pos;
	div.style.cssFloat = f;
	div.style.width = w;
	div.style.height = h;
	div.style.id = id;
	return div;
}

function center (e) {
	var marco = e.parentNode.clientWidth;
	var ancho = e.clientWidth;
	e.style.left = (marco - ancho) / 2;
}