$('<div id="id-1234"/>').getId(); /* => 1234 */ $('<div id="id-foo"/>').getId(/-(\w+)$/); /* => foo */

jquery.getid.js

(function($) {
	$.fn.getId = function(pattern) {
		pattern = pattern || /(\d+)/;
		var id = this.attr('id');
		if (!id) return null;

		var ids = (pattern.exec(id) || []).slice(1);
		return (ids.length > 1 ? ids : ids[0]) || null;
	};
})(jQuery);