Use Google’s hosted jQuery in WordPress

If you want to speed up your WordPress site you should be using Google to host the common JavaScript libraries.

Remove the WordPress jQuery version and add the Google's.

Add the following lines to your functions.php (inside your template folder).

if ( !is_admin() ) {

 // First jQuery
 		wp_deregister_script( 'jquery' );
		wp_register_script( 'jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js', false, '1.4.2', false ); // load in footer - true
		wp_enqueue_script( 'jquery' );
		
                // Now Prototype (if you're using it)
		wp_deregister_script( 'prototype' );
		wp_register_script( 'prototype', 'http://ajax.googleapis.com/ajax/libs/prototype/1.6.1/prototype.js', false, '1.6.1', false ); // load in footer - true
		wp_enqueue_script( 'prototype' );		


               // Removing more Scripts...
              wp_deregister_script( 'scriptaculous-effects' );
}

bbPress

This code can be also used in bbPress . You just need to replace the is_admin with bb_is_admin.

Plugin Solution

Don't wanna work around files and functions?

There's a great plugin that does the work for you: Use Google Libraries.