Is Valid HTML Needed for SEO?
Does Validation Failure Affect SEO Negatively?
The simple answer is NO. Html that fails W3C validation does not necessarily adversely affect search engine ranking. I do not mean to imply faulty html is OK, it is not! Common reasons for validation failure are attributes not included in the standard, simply because they did not exist at the time the protocol was created, or back then caused display problems with early web browsers. HTML validation is more about consistency in displaying content uniformly across browsers and less about search engines parsing content.
Major websites throughout the world often do not have valid HTML, either throughout the site, or for a high percentage of pages. Google.com included
Experts Discuss Validation and SEO
Don’t take my word though, instead see what the experts have to say. Matt Cutts of Google answers the question “Is HTML validation necessary for ranking?”
WordPress SEO guru and creator of the excellent WordPress Plugin WordPress SEO by Yoast, Jooost de Valk considers minor validation errors irrelevant to SEO in this article “W3C Validation: why you should care, and why not” on yoast.com
Joost considers minor errors such as attributes are not worth worrying about, and cites the use of
target=”_blank” to open a link in a new browser window (Websites with links to external sites that open in the same window irritate me constantly), as well as the use of <b> tags instead of <strong> for bold text as two examples of HTML markup that fails validation, but will not have a negative impact on search engines.
Joost points out blatant errors causing rendering or parsing errors must be fixed:
“My conclusion thus is: both for web design & SEO reasons, you’ll want to fix any and all blatant errors that might cause bad rendering or parser issues. Don’t worry about attributes that are not allowed though…”
Majority of Websites don’t Validate
The majority of websites today do not validate! There are many reasons for these sites’ HTML not passing W3C validation tests. Most are features included that were not in existence when the validation standards were compiled. One of the most common, found on nearly every significant website are social sharing links, most of which use Open Graph meta attributes.
I mentioned the fact Open Graph meta and Facebook Like Buttons fail validation in my earlier post “W3C Validation – Is it still Relevant” on this blog. I get many referrals to this post from search terms similar to “open graph fails validation”. For everyone concerned about Open Graph Validation errors, stop worrying. Open Graph meta data must be placed in the head section of an HTML page, there is no practical workaround. If anything, using Open Graph tags is more likely to have a positive effect on search engines looking for content rich feature filled web pages to deliver to searchers (if not now, almost certainly in the future) than omitting them simply to achieve validation.
If you go down that route, your site is likely to end up being poorly ranked for lack of content a viewer will find valuable.
Ignore the validation police and other extremists who insist on creating websites without Java, Rich Media content and all other bells and whistles. (Please don’t use the comment form to tell me such and such a government agency advises internet users to turn off java and such in their browsers for security reasons – Life is too short to be paranoid).
Google Does Not Require Valid HTML
As long as Google is able to parse the page, the page will get the same ranking whether the HTML is validated or not. In simple terms Googlebot could be considered a ‘web browser’. Modern web browsers are capable of displaying invalid HTML attributes without problems. Mostly they even manage html with minor syntax errors.
Matt Cutts discusses “Why doesn’t google.com validate?” in another short video. If he doesn’t know how Google ranks webpages, no-one does.
Faulty HTML is another matter. Common errors made by HTML authors such as forgetting to close tags e.g. </p> CAN break the parsing ability of search engines, and cause irregular display of the page in a browser. These sort of errors must be fixed.
Don’t Validate – Create
Here is my advice: Stop wasting time trying to get unimportant code attributes to validate. Use the time to research and create good, original, valuable content for your website or blog. Most of us today are using a Content Management System like WordPress, Drupal or Joomla etc., to manage the backroom stuff – let it do the code stuff. If you want to fix code – there are more important things to improve on page SEO than validating attributes e.g. correcting the paragraph heading markup for sidebar widget titles.
Nothing however will have a more positive result on search engine results than CONTENT. Regularly published new original, well written content.