<?php
/**
* The Header for our theme.
*
* Displays all of the <head> section and everything up till <div id="main">
*
* @package WordPress
* @subpackage Twenty_Eleven
* @since Twenty Eleven 1.0
*/
global $is_iphone;
if ( $is_iphone || $_GET['iam']=='testing' ) {
include( STYLESHEETPATH . '/mobile/header.php' );
} else {
include( STYLESHEETPATH . '/inc_header.php' );
}
?>
Basically, the proper way to use $is_iphone. This example uses it to call two different header.php include files, but it could be used to call different css files or different template files, or whatever, basically. inc_header.php is the default header.php for the site.