How do I add a simple jQuery script to WordPress?

If you use wordpress child theme for add scripts to your theme, you should change the get_template_directory_uri function to get_stylesheet_directory_uri, for example :

Parent Theme :

add_action( 'wp_enqueue_scripts', 'add_my_script' );
function add_my_script() {
    wp_register_script(
        'parent-theme-script', 
        get_template_directory_uri() . '/js/your-script.js', 
        array('jquery') 
    );

    wp_enqueue_script('parent-theme-script');
}

Child Theme :

add_action( 'wp_enqueue_scripts', 'add_my_script' );
function add_my_script() {
    wp_register_script(
       'child-theme-script', 
       get_stylesheet_directory_uri() . '/js/your-script.js', 
       array('jquery') 
    );

    wp_enqueue_script('child-theme-script');
}

get_template_directory_uri : /your-site/wp-content/themes/parent-theme

get_stylesheet_directory_uri : /your-site/wp-content/themes/child-theme

You can add jQuery or javascript in theme's function.php file. The code is as below :

add_action( 'wp_enqueue_scripts', 'add_my_script' );

function add_my_script() {
wp_enqueue_script(
    'your_script_name', // your script unique name 
    get_template_directory_uri().'/js/your-script.js', //script file location
    array('jquery') //lists the scripts upon which your script depends
);
}

For more detail visit this tutorial : http://www.codecanal.com/add-simple-jquery-script-wordpress/

After much searching, I finally found something that works with the latest WordPress. Here are the steps to follow:

1. Find your theme's directory, create a folder in the directory for your custom js (custom_js in this example).
2. Put your custom jQuery in a .js file in this directory (jquery_test.js in this example).

3. Make sure your custom jQuery .js looks like this:

   (function($) {
   $(document).ready(function() {
   $('.your-class').addClass('do-my-bidding');
   })
   })(jQuery);
   

4. Go to the theme's directory, open up functions.php

5. Add some code near the top that looks like this:

   //this goes in functions.php near the top
   function my_scripts_method() {
   // register your script location, dependencies and version
      wp_register_script('custom_script',
      get_template_directory_uri() . '/custom_js/jquery_test.js',
      array('jquery'),
      '1.0' );
    // enqueue the script
     wp_enqueue_script('custom_script');
     }
   add_action('wp_enqueue_scripts', 'my_scripts_method');
   

6. Check out your site to make sure it works!

I know what you mean about the tutorials. Here's how I do it:

First you need to write your script. In your theme folder create a folder called something like 'js'. Create a file in that folder for your javascript. E.g. your-script.js. Add your jQuery script to that file (you don't need <script> tags in a .js file).

Here is an example of how your jQuery script (in wp-content/themes/your-theme/js/your-scrript.js) might look:

jQuery(document).ready(function($) {
  $('#nav a').last().addClass('last');
})

Notice that I use jQuery and not $ at the start of the function.

Ok, now open your theme's functions.php file. You'll want to use the wp_enqueue_script() function so that you can add your script whilst also telling WordPress that it relies on jQuery. Here's how to do that:

add_action( 'wp_enqueue_scripts', 'add_my_script' );
function add_my_script() {
    wp_enqueue_script(
        'your-script', // name your script so that you can attach other scripts and de-register, etc.
        get_template_directory_uri() . '/js/your-script.js', // this is the location of your script file
        array('jquery') // this array lists the scripts upon which your script depends
    );
}

Assuming that your theme has wp_head and wp_footer in the right places, this should work. Let me know if you need any more help.

WordPress questions can be asked over at WordPress Answers.