Borys

<p>With this “Swaysmart” plugin will be able to inject HTML tags, JS and CSS codes to <code><head></code> easily.</p>
<h4>Benefits of the plugin:</h4>
<ul>
<li>You will be able to import swaysmart jscript code, meta-informations, CSS and JS codes to <code><head></code></li>
<li>Easily insert codes to single post and page headers, in addition to default codes.</li>
</ul>
<h4>Important Links</h4>
<ul>
<li><strong>[Latest FAQs and Help Article][4]</strong></li>
</ul>


Swaysmart

Swaysmart plugin enables you to add swaysmart scripts to WordPress header.

Anand Kumar

jamify

Digital Liberation

<p>An essential WordPress plugin to easily insert scripts and styles (like Google Analytics, CSS, etc.) into your website’s header and footer.</p>
<p>Looking for a way to add Google Analytics, Facebook Pixel, or custom tracking code to your website’s header or footer?</p>
<p>Header and Footer Scripts is a simple yet powerful plugin that lets you inject code—such as Google Analytics, custom CSS, Facebook Pixel, and chat widgets—directly into your site’s header (<code><head></code>) or footer.</p>
<p>No bloat, no ads. This lightweight plugin simply does what it says: inserts code into your header and footer efficiently.</p>
<p>All you have to do is add the appropriate HTML code.</p>
<p>Don’t forget to wrap your code with proper tags.</p>
<pre><code><script type="text/javascript">
YOUR JS CODE HERE
</script>
</code></pre>
<p>Or for CSS:</p>
<pre><code><style type="text/css">
YOUR CSS CODE HERE
</style>
</code></pre>
<h4>Why use this plugin:</h4>
<ul>
<li>Insert scripts globally into the header and footer of your entire website.</li>
<li>Supports all script types including HTML, JavaScript, and CSS.</li>
<li>Add specific scripts to the header of individual posts or pages.</li>
<li>To insert code to Custom Post Type [New Feature].</li>
</ul>
<p>The plugin should be compatible with WooCommerce.</p>
<h4>What it does not offer</h4>
<ul>
<li>You can’t insert/execute PHP codes.</li>
</ul>
<p>Almost all WordPress themes support this “Header and Footer Scripts” plugin. If the codes are not appearing in your site [ask for support] or look at your theme file if they have standard <code>wp_head</code> and <code>wp_footer</code> hooks.</p>
<h4>Important Links</h4>
<p>For further information you are welcomed to follow these links:</p>
<ul>
<li><strong><a href="https://github.com/anandkumar/header-and-footer-scripts/wiki" rel="nofollow ugc">Read Documentation</a></strong></li>
<li><strong><a href="https://wordpress.org/support/plugin/header-and-footer-scripts/" rel="ugc">Get Support</a></strong></li>
<li><strong><a href="https://github.com/anandkumar/header-and-footer-scripts" rel="nofollow ugc">GitHub Repository</a></strong></li>
</ul>


Header and Footer Scripts

good

Como es posible que al desinstalar el plugin, si no has borrado el script te deje el código ahi metido. Y luego a averiguar de donde vienen los errores. 

Al desinstalar te deja el código

Header and Footer Scripts plugin allows you to add scripts to WordPress site's  and just before closing  tag.

Swaysmart vs Header and Footer Scripts