Q. I had Google Chrome for Windows set so web pages couldn’t start playing videos, but I have noticed over the past few months that the clips play anyway. I didn’t change any of the browser settings, so what happened?

A. You may not have changed the browser’s settings, but the websites you use may have changed the way they handle video. For years, many sites used additional plug-in software like Adobe Flash to show videos — and most web browsers had settings to stop the plug-in software from automatically playing the clips when the page loaded.

Browser extenstions like Disable HTML5 Autoplay can help keep clips from starting when a web page loads on Google Chrome.

However, many sites have gradually switched from using the video plug-in software and are now using HTML5, which is a language for creating web pages that embeds the clips in the page. Because the plug-in software you are blocking in the browser settings no longer controls the video, the clip often starts rolling when the page loads.

While most browsers do not include easily reached settings to stop the autoplay videos, you do have some workarounds. For Google Chrome, one option is to go to the online Chrome Web Store and search for the free Disable HTML5 Autoplay extension.

Once you install the extension, it should prevent audio and video clips on web pages from playing automatically. You can turn the extension off or on from its icon in the Chrome toolbar. A version of the Disable HMTL5 Autoplay extension is also available for those using the Opera browser.