The missing jQuery function to easily remove classes matching a filter -- combines `$el.removeClass` and `$.grep`.

jquery.removeClassWhere.js

$.fn.removeClassWhere = function (filter) {
	/// <summary>
	///    Remove classes matching a filter fn(class, index_in_list) -- combines .removeClass and .grep
	///   <example>$('.things').removeClassWhere(function (cl) { return -1 != cl.indexOf(matches); });</example>
	/// </summary>

	return $(this).removeClass(function (i, classes) {
		return $.grep(classes.split(' '), filter).join(' ');
	});
};//--	fn	removeClassWhere

$.fn.removeClassWith = function (matches) {
	/// <summary>
	///   Remove classes matching a value -- combines .removeClass and .grep
	///   <example>$('.things').removeClassWith('something-you-dont-want')</example>
	/// </summary>

	if (!$.isArray(matches)) {
		return $(this).removeClassWhere(function (cl) {
			return -1 != cl.indexOf(matches);
		});
	}

	return $(this).removeClass(function (i, classes) {
		// http://stackoverflow.com/a/9930447/1037948
		return $.grep(classes.split(' '), function (cl) { return $.inArray(cl, matches) < 0; }).join(' ');
	});

};//--	fn	removeClassWhere