And don’t forget about mobile browsers. Sure, their improving, like Apple’s mobile Safari browser on the iPhone, but it’s still a lot easier to use a mobile-specific version of a site than zooming and scrolling around on the tiny screen.

As usual, PHP has a solution. That solution comes in the form of the global variable $_SERVER['HTTP_USER_AGENT']. It holds a string that contains a bit of information about the browser and platform a user us using. By searching through the string, you can figure out what browser your users are browsing with, and write-in the right code depending on the browser. You can do this in as simple, or as complicated, of a way as you want.

You can simply write-in a call to a different stylesheet, or in the case of the iPhone, an entirely different template. Using echo, header(), and include(), you have plenty of different ways to do this. Here is a simple example:

$browser = strtolower($_SERVER['HTTP_USER_AGENT']);

if (strpos($browser, 'msie')) {
include 'internetexploder.php';
}
else {
include 'normal.php';
}

?>
This is a great way to support old browsers. You can just feed them a simpler template.

Further Reading

• Browser ID (User-Agent) Strings