HELP onClick displaying img & desc

[dinosaur]

I managed to get the images to display howevr I can not get the description to change. I must have spent 40 hrs reading, trying and extremely frustrated. I'm very familiar with html but not a pro and getting into learning javascript. I'm a retired mainframe systems & applications programmer (35 years) and know this can be done but I lack the knowledge on how to do it. Any help will be extremely appreciated.
Attached is the code.
Thanks in Advance
Bill

[dinosaur]

Thanks Dave for your help. The getElementByid I could not get to work no matter what I did. After hours of searching I found something that works with an array. Is there any one source or book that gives you everything simple (how to)about Javascript? All I wanted to do was take a line of text from a table (ARRAY) and put in to the div. I'm not interested in bouncing, fading, reverse images, neon, shrinking etc text at present. Just plain vanilla javascript.
Thanks for your help and pointing me in the right direction.
A DINOSAUR