Question

how to write code JavaScript to slide show image

Answer 1

After a short search, I found these two things that might complement each other:
1. This is a nice tutorial, that shows how to write such a slideshow completely on your own: http://mrbool.com/how-to-create-a-slideshow-in-javascript-for-beginners/28045
2. If you want to have some advanced functionality, you might have a look at this library: http://www.slidesjs.com/
I would suggest to have a look at both. For real world use, you will probably use the library, because it would be much unnessessary work to write such an extended functionality by yourself, but without the understanding of the basics, provided in the tutorial, you will not be able to use the library right.