function MYTHEME_button($element) {
   if ($element['#value'] == t('Search')) {
    $element['#src'] = drupal_get_path('theme', 'MYTHEME') . '/images/search_button.png';
    $element['#button_type'] = 'image_button';
  }
  if ($element['#button_type'] == 'image_button') {
     return theme_image_button($element);
  }
  else {
    return theme_button($element);
  }
}

The above code goes into your template.php file in your theme folder. Make sure to rename MYTHEME with your theme name. You can look up $element['#value'] from the page code, it is the ‘value’ of the button element. The code snippet is for Drupal 6.

But there is another big player lurking in the shadows that may come out with some very surprising products soon. With the acquisition of Palm, HP, the largest PC maker, has bet big on the smartphone market. And the key here is the webOS. Its elegant architecture and intuitive UI are what make it all so interesting.

The development of the second generation of the platform is going at full speed. Just a few days ago, HP announced an early developer release of webOS 2.0 which comes with a slate of new features, including JavaScript Services, which means that not only webOS apps, but also services can be written entirely in JavaScript, deprecating the need for Java runtime. If you have read my last rant, I am particularly interested in the Node.js framework. And this particular framework now powers JavaScript Services for webOS 2.0. This is a further shift away from standard C/C++/Java and towards JavaScript.

If HP succeeds with upcoming smartphone products and builds a healthy app ecosystem, the role of JavaScript will be further expanded. It is no longer a scripting language living inside your browser. JavaScript is quickly becoming a universal language that is everywhere – from your browser to your phone OS to big iron on the server-side.

It is unquestionable that JavaScript has firmly established itself as a de-facto standard for client-side apps. But how about the back end? And is there really a need for JavaScript in the world of racks of servers running Apache, PHP, Python, Tomcat and Java in huge datacenters? After all, existing technologies have proven themselves. They bear the load of the Internet and quite successfully.

Turns out, old server-side technologies are not designed with real-time user interaction in mind. They are good at serving massive amounts of pages and have caching and scaling technologies to cope with increased load, but they are not really good for having constant back and forth communication with the user, which requires passing small amounts of data every time at a low latency.

Enter Node.js. It was developed by Ryan Dahl and made waves in the JS community last year. Node.js essentially implements the entire web stack with an event-oriented philosophy in mind. No more threads, no more I/O bottlenecks reading from file and database connections, it’s all callbacks. As in your browser.

This opens up new horizons for JavaScript. Not only it can be introduced to server-side, but it can provide some very real speed improvements. The technology is in its infancy at the moment, but the potential is there. Check out talk by Ryan Dahl.

Who knows, maybe in 5 years there will be a massive migration to frameworks based on Node.js. Just like there is a massive migration from static webpages to rich web apps today.