HTML Checking for Large Sites

Rocket Validator automatically checks your pages on the W3C Validator.

Bad value X for attribute “height” on element “iframe”: Expected a digit but saw “%” instead.

The <iframe> element, used to embed another document inside the current document, accepts both attributes width and height which must be valid non-negative integers. Percentages are not allowed for these attributes.

Check the iframe spec.

Related W3C validator issues

Still checking your large sites one page at a time?

Save time using our automated web checker. Let our crawler check your web pages on the W3C Validator.