Use jquery on a wordpress site

functions.php

<? php
function my_init() {
if (!is_admin()) {
// comment out the next two lines to load the local copy of jQuery
wp_deregister_script('jquery');
wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js', false, '1.5.2');
wp_enqueue_script('jquery');
}
}
add_action('init', 'my_init');
?>

JQuery comes bundled with wordpress from 2.4 (I think) onwards. In order to use a jquery script within a template three things are required. Firstly the add the above snippet to the functions.php file. The function my_init will then call the jquery library either from wordpress itself or from the google server. The google way is a better alternative as lots of sites use that link and it will probably already be cached in the users browser, which of course will make things faster. The wp_head(); needs to be in the header.php of course.

Secondly I've found that placing your jquery script inside header.php doesn't seem to work. So I simply embedded it inside script tags within a custom page template and that does the job.

Thirdly, you can't use the $ symbol to represent the jquery object because wordpress is in noConflict mode so you have to use jquery or rather jQuery instead. For a short script this is fine but for longer scripts it may be worth coming out of noConflict mode to avoid the code clutter. Find / Replace doesn't take long though.