This script is a fully functional html page with a javascrip script. Just change the website destination (defualt is google) and the time (in ms). Feel free to add more html or CSS onto the script, I don't mind what you do with this.
You can see it in action by visiting https://danielgray.me/github . Don't worry, it brings you back to my github page!
#Advice I recommend either locally sourcing the js script, or hosting it in a file or cdn section of your website (well what ever you call yours) Then just change the things that obviously need changing, and thats it!