Most top-ranking websites fail HTML validation. Google explains why perfect code isn’t required, and what matters instead. Many top websites have invalid homepage HTML, yet still rank well.

The topic of HTML validation has been covered here time and time again - we know Google doesn't downgrade or boost a web site with bad or good HTML validation. We also know that there are cases were ...

HTML5 form field validation also works with numeric input types and with the “required” specification. Suppose we enhanced the above HTML to add an input field with “required” and another input field ...