function showCategory(node) {
	var category = node.parentNode.parentNode.className;	
	hideAllCategories();
	showCategoryByName(category);
}

function hideAllCategories() {
	var categories = $A(document.getElementsByClassName('category'));
	categories.each(function(node){
		Element.hide(node);
	});
	Element.show('showAllLink');
}

function showAllCategories() {
	var categories = $A(document.getElementsByClassName('category'));
	categories.each(function(node){
		Element.show(node);
	});
	Element.hide('showAllLink');
}

function showCategoryByName(name) {
	var categories = $A(document.getElementsByClassName('category'));
	categories.each( function(node){
		if (Element.hasClassName(node,name)) {
			Element.show(node);
		}
	});


}