I have implement jCarousel onto my website, my jCarousel has 8 items on each page, when user click "Next" button, then jCarousel will display item 9 until item 16. I want to execute a certain codes only when jCarousel is displaying item 1 to item 8. In other word, I want to execute the codes on 1st page only. In other word, I want to execute the codes before click the "next" button. How to do that? I not sure which 1 should I use? Should I use itemFirstInCallback or itemVisibleInCallback or buttonNextCallback?

I refer to this website http://www.themosaicdesigns.com/demo/jQuery/jCarousel/ but there is not example or guideline about how to use them. Can anyone guide me how to use those functions? Thank you.