Add keyboard functionality – (File used before has changed)

I was wondering if there was a way to use keyboard functionality to move the sliders left and right? I find the post that resolved it it before, but it said to change a js file that I don’t think you have in the latest version (slideshow.js). I tried putting it at the end of the both the min files but it didn’t do anything. Where would I put the code now?

Original post: http://ww.wp.xz.cn/support/topic/add-keyboard-functionality?replies=4

Code it recommended:

$(document.documentElement).keyup(function (event) {
// handle cursor keys
if (event.keyCode == 39) {
resetInterval();
gotoView(1, true)
} else if (event.keyCode == 37) {
// go right
resetInterval();
gotoView(-1, true)
}
});
$previousButton.click(function () {
if ($buttonsActive) {
resetInterval();
gotoView(-1, true)
}
});

Thanks in advance!

https://ww.wp.xz.cn/plugins/slideshow-jquery-image-gallery/