Vladimir Prelovac

The Yahoo! Exceptional Performance team recommends <a href="http://developer.yahoo.com/performance/rules.html#js_bottom" rel="nofollow ugc">placing scripts at the bottom of your page</a> because of the way browsers download components.
“The problem caused by scripts is that they block parallel downloads. The HTTP/1.1 specification suggests that browsers download no more than two components in parallel per hostname. If you serve your images from multiple hostnames, you can get more than two downloads to occur in parallel. While a script is downloading, however, the browser won’t start any other downloads, even on different hostnames.
In some situations it’s not easy to move scripts to the bottom. If, for example, the script uses document.write to insert part of the page’s content, it can’t be moved lower in the page. There might also be scoping issues. In many cases, there are ways to workaround these situations.”
WordPress default behavior is to load javascript in the page.
This plugin will move all javascript code to the footer if the plugins have <a href="http://www.prelovac.com/vladimir/best-practice-for-adding-javascript-code-to-wordpress-plugin" rel="nofollow ugc">declared javascript properly</a>.
Plugin by <a href="http://www.prelovac.com/vladimir" rel="nofollow ugc">Vladimir Prelovac</a>. Looking for <a href="http://www.prelovac.com/vladimir/services" rel="nofollow ugc">WordPress Services</a>?
<h3>License</h3>
This file is part of Footer JavaScript.
Footer JavaScript is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Footer JavaScript is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Footer JavaScript. If not, see <a href="http://www.gnu.org/licenses/" rel="nofollow ugc">http://www.gnu.org/licenses/</a>.

JavaScript to Footer

I used and face some of bad experience with it 

Can't give perfect result

This plugin automatically moves JavaScript code to page footer, speeding up page loading time.

Adnan

WPBrigade

Muhammad Irfan

WP Headers and Footers plugin helps you to insert code to your WordPress website headers and footers section like Google Analytics tracking code, Facebook Pixels code, Google Optimize code for A/B testing, Custom CSS code, and more. You don’t need to edit the theme files to insert the code.
The simple interface of this plugin allows you to add code and different scripts from one place to your WordPress website (Headers, Footers, and Body section).
Features
<ul>
<li>Insert code to your WordPress headers & Footers</li>
<li>Insert Google Analytics Code to any WordPress theme</li>
<li>Insert Facebook Pixels Code</li>
<li>Add Google Optimize Code for A/B testing ( Ab Testing )</li>
<li>Add Google search console authentication code to any theme for verification</li>
<li>Add Custom CSS, any script, and HTML to your website 
Google Tag Manager code/script insertion</li>
<li>You can also insert code to your website body section 
Can add Bing webmaster tool code for website verification 
Add Google AdSense code</li>
</ul>
If you find our plugin useful, please leave a good rating/review and check our other plugins.
<ul>
<li><a href="https://analytify.io/ref/73/?utm_source=wp-headers-and-footers&utm_medium=readme&utm_campaign=pro-upgrade" rel="nofollow ugc">Analytify – Google Analytics Plugin</a></li>
<li><a href="https://loginpress.pro/" rel="nofollow ugc">LoginPress</a> – For Custom login page and login page security</li>
<li><a href="https://simplesocialbuttons.com?utm_source=wp-headers-and-footers&utm_medium=readme&utm_campaign=pro-upgrade" rel="nofollow ugc">Simple Social Buttons</a> – Plugin for Social share buttons and social icons</li>
<li><a href="https://wordpress.org/plugins/related-posts-thumbnails/">Related Posts Thumbnails Plugin</a> – For related posts/products</li>
<li><a href="http://wpbrigade.com/recommend/maintenance-mode?utm_source=wp-headers-and-footers&utm_medium=readme&utm_campaign=pro-upgrade" rel="nofollow ugc">Under Construction, Coming Soon & Maintenance Mode</a> – Plugin for Under construction & Coming soon page</li>
</ul>

Insert Headers And Footers

I like its simple design which doesn't add menu item on top level of WP admin menu. Recommended for client works and who prefer to keep WP admin menu simple. I hope you continue its simple style than adding functionalities.

Simple UI

Include inline javascript, stylesheets, CSS code or anything you want in Header and Footer areas of your WordPress with ease.

JavaScript to Footer vs Insert Headers And Footers