Writing a Custom Widget for Google Calendars

<entry>
	<id>...</id>
	<published>2011-08-08T14:16:34.000Z</published>
	<updated>2011-08-08T14:16:34.000Z</updated>
	<category scheme='http://schemas.google.com/g/2005#kind' term='http://schemas.google.com/g/2005#event'/>
	<title type='text'>Sangria &amp; Tapas Tasting</title>
	<content type='text'>
		BLAH BLAH BLAH
	</content>
	<link rel='alternate' type='text/html' href='https://www.google.com/calendar/event?eid=cWcxa2U0ZnRhYnUwZWRpYzdnZTJzdXBwajggNDY1OWlmNW1yZGZ2a3Y0YWIzcGZqczY1Z2NAZw' title='alternate'/>
	<link rel='self' type='application/atom+xml' href='https://www.google.com/calendar/feeds/XXXXXX%40group.calendar.google.com/public/full-noattendees/qg1ke4ftabu0edic7ge2suppj8'/>
	<author><name>Calendar Name</name></author>
	<gd:comments>
		<gd:feedLink href='https://www.google.com/calendar/feeds/XXXXX%40group.calendar.google.com/public/full/qg1ke4ftabu0edic7ge2suppj8/comments'/>
	</gd:comments>
	<gd:eventStatus value='http://schemas.google.com/g/2005#event.confirmed'/>
	<gd:where valueString='Tasca Restaurant - 1612 Commonwealth Ave, Brighton, MA 02135 '/>
	<gd:when endTime='2011-08-15T21:00:00.000-04:00' startTime='2011-08-15T19:00:00.000-04:00'/>
	<gd:transparency value='http://schemas.google.com/g/2005#event.opaque'/>
	<gCal:sequence value='0'/>
	<gCal:uid value='qg1ke4ftabu0edic7ge2suppj8@google.com'/>
</entry>

<h2>Upcomming Events</h2> 
<div id="status" style="display:none"></div> 
<div id="calendarFeed"></div>

<!-- discovered on http://blog.csdn.net/runupwind/article/details/1655837 -->
<script language="javascript"  type="text/javascript">
<!--
// the max number of evewnts to show
maxEvents = 7;
 
var RSSRequestObject = false; // XMLHttpRequest Object
var Backend = '/wp-content/uploads/2011/08/demo/backend.php'; // Backend call to same domain proxy (prevents 'is not allowed by Access-Control-Allow-Origin.')
window.setInterval("update_timer()", 1200000); // update the data every 20 mins
 
 // DO NOT EDIT BELOW
 
if (window.XMLHttpRequest) // try to create XMLHttpRequest
	RSSRequestObject = new XMLHttpRequest();
 
if (window.ActiveXObject)	// if ActiveXObject use the Microsoft.XMLHTTP
	RSSRequestObject = new ActiveXObject("Microsoft.XMLHTTP");
 
 
/*
* onreadystatechange function
*/
function ReqChange() {
 
	// If data received correctly
	if (RSSRequestObject.readyState==4) {
 
		// if data is valid
		if (RSSRequestObject.responseText.indexOf('invalid') == -1) 
		{ 	
			// Parsing Feeds
			var node = RSSRequestObject.responseXML.documentElement; 
 
			// Get the calendar title
			var title = node.getElementsByTagName('title').item(0).firstChild.data;
 
			content = '<div class="channeltitle">'+title+'</div>';
 
			// Browse events
			var items = node.getElementsByTagName('entry');
			if (items.length == 0) {
				content += '<ul><li><div class=error>No events</div></li></ul>';
			} else {
				content += '<ul>';
if(maxEvents > items.length) maxEvents = items.length;
				for (var n=0; n <= maxEvents-1; n++)
				{
					var itemTitle = items[n].getElementsByTagName('title').item(0).firstChild.data;
 
					// may have empty content if no event details were added
					try{
						var Summary = items[n].getElementsByTagName('content').item(0).firstChild.data;
					}catch(e){
						var Summary = '';
					}
 
 
var eventId="";
var baseUrl=items[n].getElementsByTagName('link').item(0).attributes.getNamedItem("href").value;
//alert(calId);
 
					var itemLink = baseUrl;
console.log(items[n].getElementsByTagName('when'));
var roughStartDate=items[n].getElementsByTagName('when').item(0).attributes.getNamedItem("startTime").value;
 
 
 
					try 
					{  var mydate=new Date(roughStartDate);
var readAs="" + (mydate.getMonth()+1) + "/" + mydate.getDate() + "/" + mydate.getFullYear();
						var itemPubDate = '<span class="event-date">['+ readAs+']</span> ';
					} 
					catch (e) 
					{ 
						var itemPubDate = '';
					}
 
 
					content += '<li>'+itemPubDate+'<a href="'+itemLink+'"><span class="event-summary">'+itemTitle+'</span></a></li>';
				}
 
 
				content += '</ul>';
			}
			// Display the result
			document.getElementById("calendarFeed").innerHTML = content;
 
			// Tell the reader the everything is done
			document.getElementById("status").innerHTML = "Done.";
 
		}
		else {
			// Tell the reader that there was error requesting data
			document.getElementById("status").innerHTML = "<div class=error>Error requesting data.<div>";
		}
 
		HideShow('status');
	}
 
}
 
/*
* Main AJAX RSS reader request
*/
function RSSRequest() {
 
	// change the status to requesting data
	HideShow('status');
	document.getElementById("status").innerHTML = "Requesting data ...";
 
	// Prepare the request
	RSSRequestObject.open("GET", Backend , true);
	// Set the onreadystatechange function
	RSSRequestObject.onreadystatechange = ReqChange;
	// Send
	RSSRequestObject.send(null); 
}
 
/*
* Timer
*/
function update_timer() {
	RSSRequest();
}
 
 
function HideShow(id){
	var el = GetObject(id);
	if(el.style.display=="none")
	el.style.display='';
	else
	el.style.display='none';
}
 
function GetObject(id){
	var el = document.getElementById(id);
	return(el);
}
 RSSRequest();
//--></script>

<?php
// Change this with your Google calendar feed
$calendarURL = 'https://www.google.com/calendar/feeds/the-final-url-for-your-public-calendar';
 
 
// Nothing else to edit
$feed = file_get_contents($calendarURL);
header('Content-type: text/xml');
echo $feed;
die();
?>