
Let's get started and see how we can easily block the auto-play of videos, either through a native browser functionality or through an effective add-on. Avoid old versions of these browsers to get the best results.
Stopping Video Autoplay in Firefox Web Browser
Firefox natively supports the video autoplay blocking option within its settings. There's no need to install a 3rd party add-on or extension. And, it works flawlessly without any issues. Here's how to disable video autoplay within Firefox.Go to Settings → Privacy & Security → Permissions → Autoplay → Settings... option.
It'll open a dialogue box as shown below.

Stopping Video Autoplay in Google Chrome
Though Google Chrome provides an option to somewhat restrict the autoplay of videos in its settings, it's not an absolute blocking option. Apart from activating that option, one also needs an add-on to make things work. Let's see how to do it.First, the native settings partially get the job done on a conditional basis. Though it doesn't solve our problem, it's good to know about the setting, as it may change in the future to support full video autoplay blocking.
Go to Settings → Privacy and security → Additional content settings → Sound option. Here you can select to stop websites from playing sound automatically. This essentially blocks video as well on some websites. But, it doesn't work everywhere.
A better way is to install an extension called HTML Content Blocker which delivers what we want.
After installing the add-on, make sure you select the Media tab as shown below.

Stopping Video Autoplay in Microsoft Edge
Quite similar to Google Chrome, Edge does provide a setting to stop video autoplay on a conditional basis. The deciding factor is whether, on a website, you've interacted with the media in the past or not. So, first, we'll enable this feature and then will go on with the add-on configuration.Go to Settings → Cookies and site permissions → Media autoplay option. Here, select the Limit option from the drop-down menu. But, this isn't going to block every video on every website.
To make that happen, install the Disable HTML5 Autoplay extension. No manual configuration is needed after installation. It just works out of the box.
