Top "W3c-validation" questions

You can use W3C validation services to check HTML documents, CSS stylesheets, Atom/RSS feeds, and more.

X/Html Validator in PHP

First thing: I know that there is interface to W3C validator: http://pear.php.net/package/Services_W3C_…

php html validation xhtml w3c-validation
Is it valid to put h3 (or any heading) inside td tags?

The question is asked for TH tags, but I couldn't find one for TD tags. Can I put headings inside &…

html html-table w3c-validation html-heading
W3C don't validate Viewport

W3C don't validate my viewport meta tag any idea why? <title>DIDIx13</title> <meta …

html w3c w3c-validation
Bad value for attribute action on element form: Must be non-empty

I have a regular form on my php file, after it's submitted it has to echo a message. By putting …

php html w3c-validation
Element name gcse:searchbox-only cannot be represented as XML 1.0

I am getting the following error in w3 validator, Line 62, Column 140: Element name gcse:searchbox-only cannot be represented as XML 1.0. …

html xml validation w3c-validation
Validation error: Byte-Order Mark found in UTF-8 File

I'm working on a website and while displaying it on Firefox is fine, on IE I've got a lot of …

html utf-8 w3c-validation byte-order-mark
Visual Studio HTML5 Validation: Element 'img' cannot be nested within element 'a'

I've run into this curious validation error in Visual Studio 2010 with HTML5 validation selected: Is this a validation error (legitimate …

visual-studio-2010 html w3c-validation
How can I avoid the "Bad value language for attribute name on element meta" HTML validation error?

I'm getting this error when I validate my HTML using the W3C validator: Bad value language for attribute name …

html w3c-validation meta
Add form to table rows

Which is a valid way (if any) to add a form to table rows? I have the following situation: <…

html forms w3c-validation tablerow
is -negative margin or padding invalid CSS according to W3C?

is -negative margin or padding are invalid CSS aaccording to W3C ?

css w3c w3c-validation