HTML5 `<link rel=“shortcut icon” />`

Question

The WHATWG document for HTML5 says that the rel attribute must contain values that are space-separated, and then it gives a table of allowed values.

Answer 1

Although it is still in its experimental stage (because HTML5 dev is ongoing), the w3.org HTML5 Markup Validator is a good online tool you can check out. I used it extensively about 6 months ago and it always gave back accurate HTML5 syntax reports.