Need help with 3 image slideshow JavaScript.

Need help with 3 image slideshow JavaScript.

a.    Select one of the images to load automatically  when the web page loads by modifying the HTML and placing a file name in the empty src property of the img tag with id="img2"
b.    Using JavaScript write the necessary functions to start the slideshow automatically and continuously cycle through the selected images displaying each one for 5 seconds.


I don't know what I'm missing in my coding to make it work?


Here's my entire website

http://jsfiddle.net/eqkhgxcL/