Given a regex, will remove all CSS classes that match from an element.

removeMatchingClasses.js

jQuery.fn.extend({
	removeMatchingClasses: function(pattern) {
		return this.each(function() {
			var element = jQuery(this);
			var classes = element.attr("class").split(/\s+/);
			jQuery.each(classes, function(idx, class) {
				if (class.match(pattern)) element.removeClass(class);
			});
			return this;
		});
	}
});