var PrototypeExtentions = {
	getChildById: function(element, id) {
		element = $(element);
		if (element.getAttribute)
			if (element.getAttribute("id") == id)
				return element;
				
		var i, c;
		for (i=0; i < element.descendants().length; i++) 
		{
			c = element.descendants()[i].getChildById(id);
			if (c != null)
				return c;
		}
		
		return null; 
	}
}

Element.addMethods(PrototypeExtentions);