The details of the errors are seen when looking the HTML source of the page.The extension is based on Tidy and Open SP (SGML Parser). But mostly,- The SGML parser is the same program than the one running behind validator.w3- Tidy has accessibility check for the 3 levels defined in WAI - W3 Online validator to validate HTML 5 pages The extension is translated in 17 languages.This makes finding and fixing these types of bugs much easier in those general head-scratching moments of “So why isn’t it doing what I want? Syntax errors in a web page do not commonly cause the web browser to refuse to open the page (although XHTML tends to be a lot stricter than HTML — at least when served as "[proper XML]").This is one of the biggest reasons for the rapid adoption and spread of the web.Server side validation is performed by a web server, after input has been sent to the server.
For these examples we have created our own valid/invalid CSS formatting to override the browser default. That's why you may see something like the following: Before you type anything into the box a red marker is shown.
What is the best way to start finding out what is wrong, and ensure that these pages (and any future pages you write) will be displayed properly across browsers, with no errors? There are many tools available, from the W3C and other places, that allow you to validate the code on your sites.
The most common three validators you’ll use are: In this Web Standards Curriculum article, we will cover how to use the first two of these, showing you how to validate markup, interpreting the typical kinds of results the validator gives you.
HTML, CSS, SEO, spelling, accessibility, mobility (Android/i OS), Java Script linting, and link checking with CSE HTML Validator for Windows.
Save time and eliminate many website problems that cause visitors to abandon your website.