jQuery + innerShiv, checking if it have any html5 tag on it first, see https://github.com/jdbartlett/innershiv/issues/9

gistfile1.js

(function ($) {

var init = jQuery.fn.init; rootjQuery = jQuery(document);
var html5 = 'abbr article aside audio canvas datalist details figcaption figure footer header hgroup mark meter nav output progress section summary time video'.split(' ');

$.fn.init = function (selector, context, rootjQuery) {
	if (typeof selector == 'string' && selector.indexOf('>') != -1 && selector.indexOf('<') != -1) {
		for (var i in html5) {
			if (selector.indexOf('<' + html5[i]) != -1) {
				return new init(innerShiv(selector, false), context, rootjQuery);
			}
		}
		return new init(selector, context, rootjQuery);
	}
	return new init(selector, context, rootjQuery);
};

}(jQuery));