I recently came across a script on Stack Overflow that allows me to select an image at random from an array. The script can be found here: Script to display an image selected at random from an array on page load
However, I want to take this concept further by displaying the randomly chosen image in fullscreen when the page loads. My idea is to use this image as a greeting page for my website, where visitors are greeted with a high-definition fullscreen image upon loading the page. When clicked, the image would then disappear, revealing the full website. I'm unsure of how to achieve this effect though. Any suggestions?
EDIT: I'm not looking for someone to implement this directly for me. I'm just seeking general ideas or examples (such as jsFiddles) on how to accomplish this task.