HTML Validation Error: Bad value tooltip for attribute rel on element a: Keyword tooltip is not registered

Question

Should I be concerned with the following HTML validation error?

        …rel="tooltip" data-placement="bottom" data-original-title="Permalink"></a></li>
        Syntax of link type valid for <a> and <area>:
        A whitespace-separated list of link types listed as allowed on <a> and <area> in the HTML specification or listed as an allowed on <a> and <area> on the Microformats wiki without duplicate keywords in the list. You can register link types on the Microformats wiki yourself.

Answer 1

The rel value tooltip is not allowed in HTML5.

You can use the rel values listed in the HTML5 spec, or the registered rel values in the microformats wiki.

Note that tooltip is listed in the microformats wiki (in the POSH usage section), but not in the section "HTML5 link type extensions".

Answer 2

"rel" value tooltip is not a valid attribute in html 5.

Replace rel attribute with data-rel attribute (wich is absolutely valid) in your code.

example:

$("a[rel]").tooltip(); to $("a[data-rel]").tooltip();