404 when enqueue_script using plugin_url

plugins_url will output the absolute file path of the plugins directory in your WordPress install.

This of course won’t work for a client (browser) calling a script.

To access scripts from the plugins directory, you’ll want to use plugin_dir_url() which will get you the url of the plugin directory.

Some things to note about plugin_dir_url()

You need to specify the directory of the plugin name your script is located
The function output contains a trailing slash, so you won’t need to concatenate a slash.

Lets say your plugin is called “my_plugin” and the script is located in a “js” directory, your script registration would look something like this:

wp_register_script('r_footer', plugins_dir_url() . 'my_plugin/js/responsiveFooter.js', array('jquery'),'1.1', true);

Note the omission of __FILE__ which will output the absolute path of the current file (not what you want).

If your script is in your active theme, you’ll want to use a different function: get_stylesheet_directory_uri

Some things to note about get_stylesheet_directory_uri

It requires a trailing slash unlike plugin_dir_url()
You will need to specify the directory path in the theme where your script is located.
This function works especially well if you are working with child themes, but a child theme is not required. If you are working with a child theme, this function will get the path to the style.css file in your child theme rather than the parent theme.
Note that the function is uri NOT url

So lets say your theme is called “my_theme” and the javascript is located in a “js” file, your registration script would look something like this:

wp_register_script('r_footer', get_stylesheet_directory_uri() . '/my_theme/js/responsiveFooter.js', array('jquery'),'1.1', true);

Links to documentation: