BBC old article highlighter

// ==UserScript==
// @name           BBC Date Highlighter
// @namespace      rjp
// @description    highlight old dates on the BBC
// @include        http://news.bbc.co.uk/*
// ==/UserScript==

var snapTextNodes = null;
var lu_date = null;
var now = new Date();

snapTextNodes = document.evaluate("//div[@class='ds']", document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);

if (snapTextNodes.snapshotLength > 0) {
alert("before");
	var elm = snapTextNodes.snapshotItem(0);
	var lu = elm.textContent.replace(/^.* at /,'');
	lu_date = Date.parse(lu.replace(/^(.*T), (.*)$/,"$2 $1"));
	if (now - lu_date > 3*86400*1000) {
		elm.innerHTML = "Page last updated at <span style='color:white;font-weight:bold;background-color:red;font-size:x-large'>"+lu+"</span>";
	}
}