Markup validation ensures web pages' technical qualities. W3C (World Wide Web Consortium) validation is checking if a website conforms to prescribed web design or formatting standards. If a website's pages do not adhere to W3C standards, the website is likely to have poor readability and formatting, which could lead to poor traffic.

What is W3C?

W3C stands for, as mentioned before, World Wide Web Consortium. W3C is an organisation that offers a markup validator to check web documents' validity. The organisation has been recognised for its World Wide web standards. The team running the show at W3C continues developing and maintaining web standards. Web developers use these standards as guidelines to develop code that's relevant and in line with the existing coding guidelines. Long story short, W3C writes the rulebook that web developers may use to determine whether their codes are well-written.

What is W3C Validation?

The majority of web documents are drafted using XHTML or HTML. The technical specifications that define these languages typically have a vocabulary that only a machine could read. Validation is checking documents against these specifics or constraints for quality and conformance. This is basically what the W3C validator does.

The validator processes documents created in almost all markup languages. HTML, XHTML, SMIL, MathML, and SVG are the document types supported. Web documents that are written with XML DTD or SGML could also be validated, provided the documents have declared their document type properly.

Benefits of Website Markup Validation 

Improved Search Engine Rankings

W3C validation improves a website's performance in search engines. A website's coding errors could impact its performance and affect its SEO. Search engines usually check the XHTML or HTML code of a website while searching. In case the XHTML or HTML codes found are invalid or the code does not follow rules, the search engine could remove the site from its indexes. And if there is a web page code error, robots would stop scanning the entire website's content altogether.

Propagates Best Practices

Having code that comply to standards is the ideal web design approach. Also, such coding teaches and fosters best web design practices. While several veterans know how to do errorless coding and commit minimal validation errors, beginners usually make a lot of errors. A computer validation would help beginner coders get better and make lesser mistakes going forward.

Improved User Experience

W3C-validated sites would render the best on modern browsers. Validation pushes up the functionality and usability of a site since users would less frequently encounter errors upon visiting and while navigating the site. Validation is completely compatible with an array of dynamic pages, active content, multimedia presentations, and scripting. The site validation process helps designers mend formatting mistakes that hurt website performance, and follow international standards. Also, the code used decreases in size, thereby improving efficiency. As a result, web pages get displayed much quickly and flow better compared to non-validated websites.

Browser-Friendly

Probably, the most important reason behind the introduction of W3C validation was making websites browser-friendly. Non-validated websites could display right in a browser but may not in others. Many websites face cross-browser issues. Websites not validated could present formatting problems in specific browsers. W3C-validated websites, on the contrary, work error-free on almost all browsers.

Multi-Device Accessibility

With the mobile device market's boom, a lot more people would be coming online using their mobile computers than using their traditional desktop or laptop computers. Mobile commerce would reach greater heights in the coming years, with certain sectors bound to witness increased mobile traffic. This warrants website owners maximising their websites' usability in new devices. Many website owners, unfortunately, do not make full use of this growth, by foregoing W3C validation. If you would like maximum people visiting your website, then your site's accessibility would be key.

Helps With Coding and Its Maintenance

Web pages or websites that have been duly validated would have efficiently formatted code. The pages would become a lot easier to edit, helping site owners create new pages or a fresh website altogether with similar formatting. Future websites would most likely have W3C HTML validation, W3C CSS validation, or W3C XHTML validation.

A Potent Debugging Tool

A validator would tell you where your code faltered. If your page is not displaying as per expectations, a validator would likely help you get to the root of the problem. Moreover, invalid code that displays fine in a document could cause show-stopping mistakes in another document due to the encompassing code.

Besides all the benefits, websites that have been coded to standards would last longer and be predominantly future-proofed against browser updates. In case the code is bad, your website's chances of breaking down with every browser update would be higher.

Validating Your Code

Validating HTML Code

HTML Markup Validation Service by W3C is perhaps the most popular and easiest tool available for checking and validating a web page. The tool helps spot almost all validation mistakes, ranging from ALT attributes missing for IMG tags to positioning a block-level element within an inline element. The HTML code can be graded using the web page address, directly pasting HTML code, or uploading the file.

Validating CSS Styles

Like the above tool, W3C offers another tool called the CSS Validation Service. It's arguably the CSS validation tool you need. And your CSS can be validated the way you validate your HTML. Kindly note, this tool would tag "CSS hacks" as errors. You would therefore require another method to support old-gen browsers to remain valid.

Validating WordPress Feeds

Feed validation isn't as popular as the other two tools but is still an important aspect of website validation. Fortunately, WordPress' default feeds validate perfectly. Your feeds are therefore already valid in case you have not employed a plugin that is tampering with the feeds. Moreover, there's another tool known as Unicorn by W3C, a unified validator. It offers satisfying validation results pertaining to CSS, HTML, i18n validation and feed.