Create a custom sidebar for each page or post with this Graceful Sidebar WordPress Plugin

A friend and fellow poker fan recently reached out with a wordpress question… She was looking for a way to customize a client’s sidebar content based on the page or post currently being displayed.  Well – it seemed logical so I dug in for a few minutes and came up with the Graceful Sidebar Plugin.  The plugin is very simple – but accomplishes the initial goals.  To use the plugin, simply install it, activate it and drag the Graceful Sidebar widget to your theme’s sidebar.  Then, create two custom fields in the post or page whose sidebar you want to customize – “graceful_title” and “graceful_content”… that’s it.

[download id=”7”]

Mobile Device Detection and Redirection with PHP

** Updated 04/26/2010 **  Added Google Mobile Crawling Detection
See also http://www.mlynn.org/2010/07/mobile-device-detection-and-redirection-with-perl-and-cgi/ for additional information on Mobile Browser Detection and Redirection using Perl / CGI.

Target Audience

Web Content Publishers, Web Server Administrators and anyone considering preparing and publishing content that may be consumed by users with mobile devices.

Overview

The mobile phone and computing market is exploding. With more and more phones and hand held devices gaining web browsing capability, it only makes sense to ensure that your site is at least viewable by these mobile browsers. In this article, I present one possible solution for detecting and redirecting incoming mobile browsers so you can customize and enhance the mobile users’ experience.

In this article, I’ll discuss an example web site where we want to present customized web content to four distinct types of user based on the browser device their using when they visit the site. I’ll also discuss how to enable the users to specify a preference for one of the other versions of the site. For example, if I’m an iphone user but I really want to see the full site.

Redirecting a user based on the type of device they are using is not rocket science. In fact, it can be accomplished quite simply using an apache redirect in a .htaccess file.

RewriteCond %{HTTP_USER_AGENT} ^.*iPad.*$
RewriteRule ^(.*)$ http://ipad.yourdomain.com [R=301]

The issue with this approach is that users coming to your site using an iPad will never have the ability to see the other versions of your site. for many, that may be a satisfactory solution. However, if you want users to have the ability to view a version of your site designed specifically for their type of mobile device by default – but have the option to click a link and either view or optionally set a preference for another version of the site, this article is for you.

Examples and Source Code

I know – you’re in a hurry… you’ve read the intro and you know this is what you’re after… well, here you go… The examples for this site are available for demonstration at https://mlynn.org/uatest/ and the code for this is available for download from the following link:

Version 0.3 – Includes PHP and Perl/CGI Examples
[download id=”2″ format=”1″ autop=”false”]

Version 0.2 – Includes only PHP Examples
[download id=”1″ format=”1″ autop=”false”]

You may additionally download or review the source for this example at github:
http://github.com/mrlynn/MobileBrowserDetectionExample

Before diving in to my solution, let’s cover some of the background and key factors. If you’re a seasoned web publisher and you already understand the basics of the web and how it works, you’ll probably want to skip down a bit.

There are several components involved in any web user interaction.

Web Browsing Device (Device)

This can be any device running some form of browser.  Desktop computers are the most popular devices browsing the web today but mobile devices are swiftly increasing in numbers.  According to statcounter.com, mobile browsers have experienced a 3 percent increase since 2008 and with the advent of hybrid devices such as the ipad and netbook, you can bet this number will continue to grow.

Web Browsing Program (Browser)

This refers to the program being run by the device for the purpose of browsing web content.  Popular browsers include Firefox, Google Chrome, Microsoft Internet Explorer and Opera.  Each browser communicates with web servers in a similar manner.  When the web browser contacts a web server, it sends several pieces of data identifying its program, version and even the device being used for this browsing session.

Web Server (Server)

The web server is responsible for presenting web content to the browsers.  Apache HTTPD and Microsoft Internet Information Server (IIS) are the two most popular web servers.

Web Content

This is the stuff you’re sending to the browser… the stuff you’re reading right now.  Depending on the type of site and your intended audience, you’re likely to have several types of content being delivered to your browsers.

The Conversation

When you type an address into your browser, or click on a link to a web site, the browser initiates a conversation with the target web server.  Much of this conversation is handled by the browser and hidden from you, the viewer.  The following is an example of a conversation initiated by a browser.

GET /uatest/index.php HTTP/1.1
Host: www.mlynn.org
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)

In this example, a user is requesting the following url: http://www.mlynn.org/uatest/index.php from an instance of Firefox browser running on a windows device.

Here’s a list of other possible values sent along with a request for web content.

Header Value
Host http://www.mlynn.org
Connection keep-alive
User-Agent Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.86 Safari/533.4
Referer mlynn.org
Accept application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Encoding gzip,deflate,sdch
Accept-Language en-US,en;q=0.8
Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie __utma=2051572.1472781444.1277919157.1277919157.1277919157.1; __utmc=2051572; __utmb=2051572.1.10.1277919157

Here’s a look at what your actual request headers look like when you’re browser requested this page:

And this is the response sent back to your browser from the instance of apache httpd running on my server:

Apache’s httpd server exposes the values of some of these request and response headers.  If you’re using the Pre-Hypertext Programming language – or PHP as it’s better known, you can access these values using built-in functions.  See PHP: apache_request_headers and PHP: apache_response_headers for more information.

Identifying Mobile Devices

Now that we have a good understanding of the conversation between the browser and the server, let’s focus on identifying mobile devices and redirection.  As I briefly explained earlier, the web browser identifies the browser program and version along with any requests for content from your web server.  The browser identifies these items using the string “User-Agent.”  The trick to identifying mobile devices is all about knowing what is sent in the User-Agent request field by each and every mobile device.  The following is an example sent by a mobile device.

User-Agent: Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A341 Safari/528.16

Redirecting Based on User Agent

So now we understand that the browser identifies itself, and if we’re using Apache httpd, we can access the value of that identifier. Let’s take a look a simple redirection example written in PHP.

[php]
if (preg_match(‘/iphone|ipad/’,strtolower($_SERVER[‘HTTP_USER_AGENT’]))) {
header("Location: http://mobile.mlynn.org");
} else {
header("Location: http://www.mlynn.org");
}
[/php]

This example interrogates the user agent variable using a php regular expression function and redirects accordingly. This redirection is facilitated using the PHP header() function.

There are several other mechanisms to accomplish similar redirection. For example, you could implement this redirection using a .htaccess file which would be parsed by Apache. This mechanism is discussed in detail on this blog entry. For now however, let’s stick to our PHP implementation.

If all you’re concerned about is redirecting users to another version of the site, this will probably work for you. You’ll simply need to understand and test for the right user-agent values.

However, let’s assume that we want to get a bit trickier. Let’s say we want to have different content or formatting for four separate versions of our site – one for each variant of browsing device that we want to support. One for normal desktop computer browsers, another for iPhone browsers, another for iPad users and one more for all other mobile browsing devices. The reasons for this are many and varied. You may want simply to vary the advertising code you expose to each user based on the type of device or browser they’re using.

To make this type of implementation work, I’ve created a configuration file to initialize some variables for our site. For each distinct version of the site, I’ll create a variable with the appropriate url. I’ll use these later when we write the code for our redirection script.

config.inc.php

[php]
$SITEURL=’https://mlynn.org/uatest/’;
$LOGFILE=’debug.log’;
$MOBILEURL=’https://mlynn.org/uatest/mobile/’; // Generic Mobile Device URL
$IPHONEURL=’https://mlynn.org/uatest/iphone/’; // iPhone URL
$IPADURL=’https://mlynn.org/uatest/ipad/’; // iPad URL
$NORMALURL=’https://mlynn.org/uatest/normal/’; // Normal – Full site URL
[/php]

Now let’s take a look at what our main index page or landing site will look like. This will be the initial page visited by users before being automatically redirected based on their browser device type.

[php]
$useragent=$_SERVER[‘HTTP_USER_AGENT’];
if (ismobile($useragent)) {
if (isipad($_SERVER[‘HTTP_USER_AGENT’])) {
header("Location: $IPADURL");
} else {
if (isiphone($_SERVER[‘HTTP_USER_AGENT’])) {
header("Location: $IPHONEURL");
} else {
header("Location: $MOBILEURL");
}
}
} else {
header("Location: $NORMALURL");
}
[/php]

This code snippet relies on several important custom functions: ismobile(), isiphone(), and isipad().

The first function examines the user agent value and returns a ‘0’ if the device is not recognized as a mobile device and a ‘1’ if it is mobile.

[php]
function ismobile() {
$is_mobile = ‘0’;

if(preg_match(‘/(googlebot-mobile|android|up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone)/i’, strtolower($_SERVER[‘HTTP_USER_AGENT’]))) {
$is_mobile=1;
}

if((strpos(strtolower($_SERVER[‘HTTP_ACCEPT’]),’application/vnd.wap.xhtml+xml’)>0) or ((isset($_SERVER[‘HTTP_X_WAP_PROFILE’]) or isset($_SERVER[‘HTTP_PROFILE’])))) {
$is_mobile=1;
}

$mobile_ua = strtolower(substr($_SERVER[‘HTTP_USER_AGENT’],0,4)); $mobile_agents = array(‘w3c ‘,’acs-‘,’alav’,’alca’,’amoi’,’andr’,’audi’,’avan’,’benq’,’bird’,’blac’,’blaz’,’brew’,’cell’,’cldc’,’cmd-‘,’dang’,’doco’,’eric’,’hipt’,’inno’,’ipaq’,’java’,’jigs’,’kddi’,’keji’,’leno’,’lg-c’,’lg-d’,’lg-g’,’lge-‘,’maui’,’maxo’,’midp’,’mits’,’mmef’,’mobi’,’mot-‘,’moto’,’mwbp’,’nec-‘,’newt’,’noki’,’oper’,’palm’,’pana’,’pant’,’phil’,’play’,’port’,’prox’,’qwap’,’sage’,’sams’,’sany’,’sch-‘,’sec-‘,’send’,’seri’,’sgh-‘,’shar’,’sie-‘,’siem’,’smal’,’smar’,’sony’,’sph-‘,’symb’,’t-mo’,’teli’,’tim-‘,’tosh’,’tsm-‘,’upg1′,’upsi’,’vk-v’,’voda’,’wap-‘,’wapa’,’wapi’,’wapp’,’wapr’,’webc’,’winw’,’winw’,’xda’,’xda-‘);

if(in_array($mobile_ua,$mobile_agents)) {
$is_mobile=1;
}

if (isset($_SERVER[‘ALL_HTTP’])) {
if (strpos(strtolower($_SERVER[‘ALL_HTTP’]),’OperaMini’)>0) {
$is_mobile=1;
}
}

if (strpos(strtolower($_SERVER[‘HTTP_USER_AGENT’]),’windows’)>0) {
$is_mobile=0;
}

return $is_mobile;
}
[/php]

The following functions are used to detect specific device types.

[php]
function isiphone($useragent) {
$iphone=0;
if (preg_match(‘/iphone/’,strtolower($useragent))) {
$iphone=1;
}
return $iphone;
}

function isipad($useragent) {
$ipad=0;
if (preg_match(‘/ipad/’,strtolower($useragent))) {
$ipad=1;
}
return $ipad;
}
[/php]

Now when a user visits our site, they will be redirected automatically based on the specific device they are using. This works in most cases, but let’s assume we want to give users the option of visiting a site other than the default for their device? Let’s say I’m on an iPhone – but I want to see what the real, full site looks like with my browser. To implement this, we’ll need some way for the user to specify a preference for a specific version of the site.

One way to accomplish this is using cookies. Cookies are small bits of data stored on your computer and referenced when you visit or revisit a web site.

There are several ways to set and get the value of cookies. Javascript can be used but depends heavily on the implementation of javascript on the device. Additionally, you must be certain that the user has not disabled javascript on their device in order for this to work.

Fortunately, cookies can be maintained using server-side code such as php. For our example, we’ll stick with PHP.

To accomplish setting and maintaining cookies via php for our users’ site preference, I created the following php script called setpref.php.

[php]
include_once(‘includes/config.inc.php’);
include_once(‘includes/functions.inc.php’);

$pref = (isset($_POST[‘SITEPREF’]) ? $_POST[‘SITEPREF’] : $_GET[‘SITEPREF’]);
switch ($pref) {
case ‘MOBILE’:
setcookiealive(‘SITEPREF’,’MOBILE’,time()+3600);
header("Location: $MOBILEURL");
break;
case ‘IPHONE’:
setcookiealive(‘SITEPREF’,’IPHONE’,time()+3600);
header("Location: $IPHONEURL");
break;
case ‘IPAD’:
setcookiealive(‘SITEPREF’,’IPAD’,time()+3600);
header("Location: $IPADURL");
break;
case ‘NORMAL’:
setcookiealive(‘SITEPREF’,’NORMAL’,time()+3600);
header("Location: $NORMALURL");
break;
default:
setcookiealive(‘SITEPREF’,’NORMAL’,time()+3600);
header("Location: $NORMALURL");
}
[/php]

This function relies on another function called setcookiealive which simply creates the cookie using php’s setcookie() function and also sets the value of the $_COOKIE variable so that the value is available immediately.

[php]
function setcookiealive($name,$value,$expires) {
$_COOKIE[$name] = $value;
setcookie($name,$value,$expires);
}
[/php]

In order for this to work, we need to give the user’s links to the alternate versions of the sites. Let’s look at one of the example site versions.

[php]
<?php
// Main iPad landing Page
include_once(‘../includes/config.inc.php’);
?>
<html>
<head>
<title>iPad Site</title>
</head>
<body>
<h1>iPad Site</h1>
<div id=’content’>
<h2>This is the iPad site. You got here because you are either using an iPad device or you specified a preference for the iPad site.</h2>
<p>
<?
echo "User Agent: ".$_SERVER[‘HTTP_USER_AGENT’];
?>
<p>
</div>
<div id=’footer’>
Visit Other Site Versions:
<a href="<? echo $NORMALURL;?>"/>Full Site</a> ||
<a href="<? echo $MOBILEURL;?>"/>Generic Mobile Site</a> ||
<a href="<? echo $IPHONEURL;?>"/>iPhone Site</a>
<p>
Set your Preference to other site versions:
<a href="/uatest/setpref.php?SITEPREF=NORMAL"/>Full Site</a> ||
<a href="/uatest/setpref.php?SITEPREF=MOBILE"/>Generic Mobile Site</a> ||
<a href="/uatest/setpref.php?SITEPREF=IPHONE"/>iPhone Site</a>
<p>
<?
if (isset($_COOKIE[‘SITEPREF’])) {
$sitepref=$_COOKIE[‘SITEPREF’];
} else {
$sitepref=’UNSET’;
}
print "YOUR CURRENT SITE PREFERENCE: ".$sitepref;

?>
</div>
</html>
[/php]

I’ve explained the components involved in any standard web user interaction, how they relate specifically to device detection, and I’ve showed one implementation of detection and redirection. If you’d like to implement something similar, feel free to download the code using the following link.
[download id=”1″ format=”1″ autop=”false”]

If you do end up using these scripts, drop me an email or log a comment to let me know how you made out. You can also try out this working example.

Example Site Links:

Related Sites and Interesting Links

Have a site you’d like to add to this list? Send me an email or submit a comment.

10 Tips to Help You Become a Better ExtJS, PHP, MySQL Developer

Before I begin, let me first say that I am not an expert ExtJS, PHP or MySQL developer. I have however, learned over the years from some basic design principles and tips gleaned far smarter and more talented developers than myself. I thought I’d create a post in the hope that you may benefit from what I have learned. Some of these tips will be pretty basic for most skilled developers, but it never hurts to review, right?

Audience – Who is This Article For?

This article was intended for the novice to intermediate web developer who specializes in use of the following technologies:

Tip 1 – Stop Using Print Statements to Debug

Developing solutions using the elegant Javascript framework ExtJS can be a mix of pleasure and pain.  While debugging the Javascript components is made easy with the handy Firefox extension FireBug, getting debug information back from the php side of your app can be tricky.  Especially if you’re expecting to maintain JSON communication with your javascript components. There are basically two methods of debugging the php side of your app.  You can either rely on JSON encoded strings sent back to your javascript components, decode them on the other side and display them either in and alert window, or in the console using console.log, or you can use print statements in your php.

The latter approach will commands will likely cause a javascript interpreter error and force you to reload the page to continue testing. I prefer the latter approach because its simpler.  However, instead of simply using the php echo or print commands, I like to create a logging function which uses file_print_contents to populate a debug log. Here’s my function:

function logit($text) {
    $now=date('Y-m-d h:m:s');
    $debugdata=debug_backtrace();
    $out=$now.' '.$_SERVER['SERVER_NAME'].' '.$_SERVER['PHP_SELF'].' '.$debugdata[2]['function'].' '.$text;
    file_put_contents('debug.log',$out,FILE_APPEND);
}

With this function, debugging is as easy as calling your logit() function instead of using print. I typically open another window and execute a tail -f debug.log to maintain a constant view of streamed debug data.

Tip 2 – Centralize your Database Updates

Creating a single reusable function to update your database can save your years of debugging.  It also provides a single place where you can add logging features to your updates.  For example, let’s say you want to create an update_log table for the database your updating.  This table will contain a record of every column, row and table that you’ve updated along with the mechanism used to update it and the date/time it was updated.

If you’ve got your mysql_query code scattered about your project, you’re going to need to add this logic all over the place.  If you’ve centralized your updates into a single function, you merely need to add the update_log logic to your update function.

Tip 3 – Borrow Heavily but Don’t Be A Script-Kiddie

We all do it.  Why re-invent the wheel, right?  I’m referring to the common practice of code-theft.  There are copious examples of many of the required components of most application challenges you’ll come up against.  So why not?  Why not, simply grab the code and slap it into your project?

It makes perfect sense – but you need to understand the code you’re lifting if your project is going to be a successful and supportable one.

A good friend of mine introduced me to a term over 12 years go – Script-kiddie.  A Script-Kiddie is a derogatory term used to describe someone that steals scripts or code, uses them but never fully understands how they work or in some cases, what they even do.  The term is typically used in a security context.

Simply put, don’t be one.

Tip 4 – Buy a Book (or two)

There are great books out there to help you with the PHP/MySQL/ExtJS development paradigm.  Here are a few that I own:

  1. Learning Ext JS
  2. Professional JavaScript Frameworks: Prototype,YUI, ExtJS, Dojo and MooTools (Wrox Programmer to Programmer)
  3. Learning PHP, MySQL, and JavaScript: A Step-By-Step Guide to Creating Dynamic Websites (Animal Guide)
  4. PHP and MySQL Web Development (4th Edition)
  5. PHP Phrasebook
  6. JavaScript: The Definitive Guide
  7. MySQL (4th Edition)

And here’s one that’s not fully released – but looks to be pretty awesome:

Tip 5 – Use FireBug

Firebug is a fantastic FireFox browser extension that enables you to inspect HTML and javascript, and even modify style and layout in real-time. I simply can’t imagine developing javascript, HTML or CSS based solutions without it.

Here’s a good screencast which explains the basics of getting, installing and using Firebug.

This assumes you can use the fabulous FireFox browser. In some cases, you can’t. For instance – my employer does not permit use of FireFox. In those cases, you can use IE addons to accomplish a minimal amount of the same capabilities as Firebug. Another option is to leverage the ExtJS Debug Console.

Tip 6 – Modularize Your Javascript

The ExtJS development paradigm is one that lends itself to rapid production. You’re madly cutting/pasting or typing in your component syntax and you’re application begins to take on a beautiful life of its own. It’s very easy to simply keep slapping components into your main javascript file, testing, debugging, and slapping more code on. I’m guilty. My first ExtJS application has over 4300 lines in a single javascript file… ugh… I’m embarrassed. Don’t get me wrong – the app works… it’s just nearly impossible to debug.

One way to implement modular code is to leverage iframes. The managed iframe user extension makes this very easy to do. Saki’s Example Page makes use of this extension beautifully. The code to create the main viewport and the layout panels is in one javascript file, but when you click on a link in the navigation tree, the code for the main or center panel is included in an iframe. This permits you to create one main application.js file and another separate javascript code file for each of the options in your tree.

Tip 7 – Use extjs-debug-all.js and extjs-debug-base.js During Development

To use the ExtJS Framework, you simply include the basic Javascript libraries and CSS stylesheet information in your HTML document. Here’s an example:



        Application Title
        
        
        
        




Tip 8 – Check for Trailing Comma’s

IE is much more picky about trailing comma’s than Firefox or Safari. Since I develop on a Mac, I’m forever missing trailing comma’s. I have an ancient laptop running Windows XP that I keep around for the sole purpose of testing apps in IE. Because javascript is interpreted, not compiled, you don’t get that piece of mind that comes from passing your work through the compiler before placing it in front of the user.

9 times out of 10 when I have an error in IE, it’s because of a trailing comma. ExtJS uses objects configured using JSON like syntax. Here’s an example:

var myExample = function() {
    return {
        foo: 'bar',
        boo: 'far'
    }
};

In this example myExample is an object which is configured with a function. The function in turn is configured with a return object which has parameters foo and boo. The syntax for this example is correct. Consider, on the other hand, this example:

var myExample = function() {
    return {
        foo: 'bar',
        boo: 'far',
    }
};

See the difference? That one minor, trailing comma after boo: ‘far’ will cause IE to stop interpretation of the entire javascript.

One way to catch this error is to copy and paste the source code of your javascript into JSLINT.

JSLINT will return the following:

Error:

Problem at line 4 character 19: Extra comma.

boo: ‘far’,

Problem at line 5 character 6: Missing semicolon.

}

Tip 9 – Create an Automated Backup Routine for Nightly Backups

There’s nothing worse than after weeks of steady positive progress, you suddenly find yourself unable to figure out what you’ve done to break things. Having a nightly backup strategy can provide valuable insight into the path you took to get where you are now.

For nearly every large scale project, I create a simple script to backup the code and data and ship it offsite somewhere – typically back home to my home development lab.

If you’re able to create a public/private key pair and configure passwordless login between your development environment and your home machine, you can create a simple script which can be executed automatically via cron to securely copy your development work back down to your home machine.

Here’s a link to creating a secure passwordless login scheme with SSH.

Once you have that in place, here’s a little script that you can customize to create backups for your work.

#!/bin/sh
# mlynn - standard backup script
# ----- - Remember to implement passwordless ssh
#
# Modify these variables
LOCALDIR=/Users/mlynn/Projects/WSS
REMOTEDIR=/var/www/vhosts/mlynn/httpdocs/wss/payroll/v2
LOCALEXTDIR=/Users/mlynn/www/extjs
HOST=your remote hostname.com
USER=your remote username
DATE=`date "+%m%d%Y"`
#
cd $LOCALDIR
mkdir -p backups/$DATE/v2
cd backups/$DATE/v2
scp -r ${USER}@${HOST}:${REMOTEDIR}/*.html .
scp -r ${USER}@${HOST}:${REMOTEDIR}/*.php .
scp -r ${USER}@${HOST}:${REMOTEDIR}/*.json .
scp -r ${USER}@${HOST}:${REMOTEDIR}/js .
scp -r ${USER}@${HOST}:${REMOTEDIR}/includes .
scp -r ${USER}@${HOST}:${REMOTEDIR}/images .
scp -r ${USER}@${HOST}:${REMOTEDIR}/css .
# Add additional directories or files that you want to capture
#
# This line links your local extjs directory so you don't have to download nightly
ln -s $LOCALEXTDIRs .

This will create a fully functional copy of your web development area on your local machine. The last line of that script creates a symbolic link to the ExtJS library directory on your local machine. This assumes that you don’t want to copy down the extjs javascript library distribution every night.

Make sure you modify the following variables to customize the script for use on your local machine.

LOCALDIR – this is the local directory on your home development machine.
REMOTEDIR – this is the root directory of your development work on your client or remote machine.
LOCALEXTDIR – this is the full path to the extjs libraries on your local machine.

Once you’ve got all that setup – add your script to cron to kick it off nightly (or even more frequently.)

Tip 10 – Visit ExtJS.com Often

ExtJS.com is frequently updated with new versions, featured implementations and blog posts designed to simplify use of this great framework.

The site is well organized and has several sections specifically designed to help you getting started using the framework. The Learn section is a great place to start.

Bonus Tip – Use an Alert Service To Notify You of Updates on ExtJS.com

Since timely information is very valuable when you’re working on a project with tight deadlines, you may consider using an alerting service to tell you when new information has been added to the extjs.com site. http://www.changedetect.com is one option that offers a free web site modification alerting service.