Debiprasad Sahoo

This is a very simple sidebar widget which places javascript code in the widget. In this plugin, you need to provide the url of the javascript and this plugin will use that js file source.
If you want to put any JavaScript code inside the <code><script></code> tag, then try my <a href="https://wordpress.org/extend/plugins/javascript-block-widget/" title="JavaScript Block Widget plugin" rel="ugc">JavaScript Block Widget plugin</a>.
You can also able to add JavaScript codes in text widget in sidebar. So you don’t need this plugin.
<h3>Usage</h3>
BidVertiser Ads 
BidVertiser Ads codes provide an URL of JavaScript code, which you need to include as the source in a JavaScript block. Get the url from the code generated from BidVertiser and provide while editing the widget values and you can see the ads in this sidebar widget.

Include JavaScript Widget

Allows you to insert any javascript code from a js file to your Wordpress widget

Frank Goossens

Optimizing Matters

EricJohnsonGuru

Eliminate Render-blocking Javascript in above-the-fold content with Async Javascript.
Render-blocking Javascript prevents above-the-fold content on your page from being rendered until the javascript has finished loading. This can impact on your page speed and ultimately your ranking within search engines. It can also impact your user’s experience.
Async JavaScript gives you full control of which scripts to add an ‘async’ or ‘defer’ attribute to or to exclude to help increase the performance of your WordPress website.

Async JavaScript

Plugin works as expected, settings are nice and minimal (using core styles) and there aren't any banners, notices or other marketing bloating things up.

Works great!

Async Javascript lets you add 'async' or 'defer' attribute to scripts to exclude to help increase the performance of your WordPress website.

Include JavaScript Widget vs Async JavaScript