jQuery(function($) { var eventName = 'emchange'; $.em = $.extend({ version: '1.0', delay: 200, element: $('<div />').css({ left: '-100em', position: 'absolute', width: '100em' }) .prependTo('body')[0], action: function() { var currentWidth = $.em.element.offsetWidth / 100; if (currentWidth != $.em.current) { $.em.previous = $.em.current; $.em.current = currentWidth; $.event.trigger(eventName, [$.em.current, $.em.previous]); } } }, $.em); $.fn[eventName] = function(fn) { return fn ? this.bind(eventName, fn) : this.trigger(eventName); }; $.em.current = $.em.element.offsetWidth / 100; $.em.iid = setInterval($.em.action, $.em.delay);});