A closing gate-like effect on a jQuery slideshow takes only two opposite, positioned elements to be executed on each slide in order to show the current image. These two panels slide in opposite directions, thus creating the effect of a closing and opening gate. Let's see the details.
Why jQuery is one of the most used JavaScript libraries available on the web? Perhaps it has more features than other libraries or more flexibility. Perhaps its design is better conceived. Nothing like that: jQuery is a successful project simply because it has usability in mind. Usability is a too often neglected aspect of library development. jQuery fills this gap by providing a simple way to perform tasks that other libraries tend to make too complicated for the average user. That's the jQuery's secret.
JavaScript timers constitute the inner engine of any good automated jQuery slideshow. Although timers can be really handy in most situations and case-scenarios, their rules are somewhat obscure to many developers. The point is that timers can be used in a wide range of use cases, not only in animations. For that reason, you should understand how timers work when applied to jQuery animations before developing any practical implementation that makes use of them.