Best Way to Include Scripts on a Specific Template Page

This is something that has always confused me and I could use some help.

I want to do four things directly above the closing body tag:

1. include jQuery (WordPress version is fine)
2. include a jQuery plugin dependent on jQuery beneath this
3. initialize the plugin directly underneath this plugin AND avoid conflict issues using $ instead of jQuery
4. do this only on specific page templates or theme files

I understand that I probably should be using wp_enqueue_script, but I’m not sure if I should use that in functions.php or just directly on the page where I want it.

Regarding number 3 I have seen the workarounds such as:

jQuery(function ($) {
/* You can safely use $ in this code block to reference jQuery */
});

But I’m honestly confused as to how to implement this.

What’s the best way to accomplish this?

Thanks very much.

The following (in your theme’s functions.php) will register your script, and set jQuery as a dependency. So when you enqueue it, jQuery will also be enqueued.

function my_scripts_method() {
   // register your script location, dependencies and version
   wp_register_script('my_custom_script',
       get_template_directory_uri() . '/js/custom_script.js',
       array('jquery'),
       '1.0' );

}
add_action('wp_enqueue_scripts', 'my_scripts_method');

You can then enqueue your script one of two ways. In your theme’s functions.php you can use the template_include filter the get the template being used using is_page_template()

add_filter( 'template_include', 'my_load_script_for_template', 1000 );
function my_load_script_for_template( $template ){
     if(is_page_template('my-template.php'))
        wp_enqueue_script('my_custom_script');

return $template;
}

Alternatively, if you are using 3.3+ and your theme calls wp_footer() then you can just call wp_enqueue_script('my_custom_script') inside the actual template page.