HTML Checking for Large Sites

Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.

Bad value X for attribute “src” on element “img”: Illegal character in query

The src attribute on an element <img> contains a character that is not allowed, and should be encoded.

Some typical examples include the pipe character | that should be replaced by its encoded alternative %7C , and the left square bracket [ that needs to be encoded as %5B.

Related W3C validator issues