(X)HTML5 Checker

(X)HTML5 Checker

A small extension to validate the markup of current webpage

What is (X)HTML5 Checker?
(X)HTML5 Checker is a Firefox add-on that allows you to validate the markup of current webpages. It helps you check for errors and maintain HTML5 standards in your code. This extension sends the webpage's HTML to a web service to detect errors and provides a popup list of errors, highlighting the error part and displaying the source code where the error is found. Source code can be found at the provided link.
Users: 123 ▲ 2
Rating: 3.33 (3)
Version: 0.0.3 (Last updated: 2019-04-03)
Creation date: 2018-12-05
Weekly download count: 3
Firefox on Android: No
Risk impact: Moderate risk impact
Risk likelihood: Low risk likelihood
Manifest version: 2
  • <all_urls>
  • activeTab
Size: 31.25K
Stats date:

Other platforms

Not available on Chrome
Not available on Edge
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WebExtension to validate the webpage's html using https://validator.w3.org/ web service APIs.

  • It can be used while developing the website to check for errors and maintain standards in your code.
  • It sends the current webpage’s HTML to the https://validator.w3.org/nu/ web service in order to check it for errors.
  • You can detect all the errors, in a popup list, to facilitate the refactoring of the code, the error part is highlighted and the source code is also displayed where the error is found.

Source code - https://ulmdevice.altervista.org/htmlValidator/

User reviews
I tried it briefly and disabled it. It cannot send the code of a page from my local/development server to the W3C validator. It's only useful for pages that are already live-online (public), but that's not when I do my code validation; I check my code while it's still in development. You might think it's impossible to send non-public code to the W3C validator, but I do it all the time (by Command-U to see the browser's parsed/rendered code, copy all, go to W3C, and paste into their validator). If I can go through these steps, why can't this extension do that for me? Another (minor) problem is that there doesn't seem any way to have this extension put an icon in the Firefox toolbar, like my other extensions do. (Yes I know how to customize the toolbars.) This extension seems to be only accessible by pulling down the Extensions sub-menu. Not worth the trouble. Disabled.
by LawrenceSan, 2023-12-14
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Risk impact

(X)HTML5 Checker may not be safe to use and it requires some risky permissions. Exercise caution when installing this add-on. Review carefully before installing.

Risk likelihood

(X)HTML5 Checker has earned a fairly good reputation and likely can be trusted.

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