Minor Edit to Slideshow Style Website Required (Javascript / PHP)

I have a website which needs two relatively small edits made You can see a demo of the site here: [login to view URL] Things I would like fixing: 1) Because the next slide that shows is preloaded, it takes two clicks for a newly selected genre option (the grey boxes) to start showing. I would like a solution to this so the correct results are shown on the next slide after submitting. 2) The slide animation is quite slow/choppy, I think this is caused by the Youtube iframe being loaded while it slides, so perhaps make it so the iframe loading is delayed until the slide animation is finished and everything else is done loading? Thanks, I hope this is clear and that these are easy fixes. I've included an image of the javascript so you can have a rough idea of what you'd be working with.