Sadly does not support CSS HTML Validator any longer... but maybe Marc will one day be able to add support for it back in.

Offline validation cause some false warning. For example, this code `<button class="btn btn-outline-secondary" type="submit">ค้นหา</button>` cause "Warning: missing </button>". Use W3c online return correct result.

First you have to open the DevTools and click on the Validator. This is one more click than before. And you can't see immediately that there are problems while surfing, because the icon is always grey in the toolbar. This is unfortunately a step backwards, therefore only 3 stars instead of 5 as before.

With FF 60 still sees the source generated by browser instead source generated by server. The Options of this extension are partial broken... not able to select GSML, always gets TIDY... partial working on FF 60, needs to be reworked again to be useful under FF 60 and more...

EDIT: in chrome this extension don't work anymore... won't validate my web pages, instead to see a green flag I can see only a message "Info 0 0 No HTML" and nothing other... the flag remains gray...

This happens on latest version of Chrome! Version 66.0.3359.181...