Fineswap

This plugin will make developers and site builders (hopefully very) happy.
It enables site administrators to supply additional styles or/and scripts to 
be loaded alongside the theme’s resources. It will work regardless which 
theme the site is running, which makes it brilliant for adding custom 
programming and content blocks.
Styles and scripts can be either entered manually or loaded from 
external URL’s.
Brought to you by <a href="http://fineswap.com/?utm_source=wordpress&utm_medium=plugin&utm_term=readme-desc&utm_campaign=custom-resources" title="A blog and a mobile app advocating sustainability and green living" rel="nofollow ugc">Fineswap</a> Team.

Custom Resources

Easily load additional styles and scripts (for both front and backend pages). Works by direct inline embedding or by using URL's.

Palasthotel

greatestview

CAUTION: This plugin is now deprecated! The successor plugin is <a href="https://wordpress.org/plugins/embed-javascript-file-content/" rel="ugc">Embed JavaScript File Content</a>. The new plugin is rebuild from scratch and more rock solid: It respects order and position of scripts and extra scripts added via <code>wp_add_inline_script</code> or <code>wp_localize_script</code> don’t get lost. Give it a try!
In some cases you cannot wait for a JavaScript file to load, even if it is placed early in the <code><head></code> section of your template. You can benefit from better performance, if you place the JavaScript code directly inside a <code><script></code> tag into the header. This is where this plugin comes in: It provides a filter <code>inline_javascript_in_head_handles</code>, which takes JavaScript handles, dequeues those scripts and echos their code content inline into the head section instead of linking them via a script tag.
Please beware that placing lots of JavaScript code inline in the <code><head></code> section can be critical! First you lose caching benefits and second the document size can increase easily. A general rule of thumb is that you should only consider JavaScript files for inline placement, which are critical and which have a file size lower than ~500 Bytes.
<h4>Example</h4>
<pre><code>add_action( 'wp_enqueue_scripts', 'my_scripts' );
function my_scripts() {
 // Some critical script is enqueued
 wp_enqueue_script( 'js-detection', get_template_directory_uri() . '/js/js-detection.js' );
}

/**
 * Define JavaScript handles to be echoed inline in the html head section.
 */
add_filter( 'inline_javascript_in_head_handles', 'my_inline_javascript_in_head_handles', -20 );
function my_inline_javascript_in_head_handles( $handles ) {
 $scripts = [ 'js-detection' ];

 return array_merge( $handles, $scripts );
}
</code></pre>

Inline JavaScript in Head

Boosts performance of critical short JavaScripts by placing their content directly into the HTML head.

Custom Resources vs Inline JavaScript in Head