google.load("jquery", "1");

function OnLoad(){
	var current = jQuery("#block li:first");
	jQuery("#block li").click(function(){
		
		current.children("span").removeClass("selected");
		current.children("p").addClass("invisible");
		
		jQuery(this).children("span").addClass("selected");
		jQuery(this).children("p").removeClass("invisible");
		
		current = jQuery(this);
	});
}

google.setOnLoadCallback(OnLoad);