Errors encountered validating document
Following on from the last point, special characters, particularly the ampersand should also be converted to entities when they appear in URLs.
Links to sites built in PHP are likely to include variables in their links using the .
Not to mention the search engine bots for all you SEO people – You wouldn’t want to put obstacles in their way, a clean and valid page is going to be much easier for the bots to read and scan. I see invalid HTML little like spelling mistakes, although the client probably won’t see a mistake in your code, the idea is still the same.
You wouldn’t want to supply a design full of typos or spelling errors, so you shouldn’t really settle for an HTML page full of little validation issues.
The warning for this in the W3C validator is the cryptic message are self-closing, this means they have a trailing slash before their closing bracket.
Xml Document class does not validate an XML document using either DTD or XML schema definition language (XSD) schema validation by default. You can also perform read-only validation of XML content using the xref: System. The first way to validate an XML document is to validate the document as it is loaded into an xref: System. Xml Document object using a validating xref: System. Unlike HTML, CSS is used just to display the visual aspect of a web page, therefore the statement “If it looks good in the browser, why bother validating? An invalid CSS document isn’t going to have as much affect as an invalid HTML document, but you should run a validation check just to make sure you haven’t made any typos or mistakes in your code.If you’ve used any fancy CSS3 properties, these will invalidate your document as they’re not yet part of the spec, as long as you know they’re correct they can be ignored.