Any internet browser on any device and has an iOS version for apple devices. Classroom edition features are free to use.
Time needed to learn how to use it and get going:
What CodeCombat says about CodeCombat:
Programming is magic. It's the ability to create things from pure imagination. We started CodeCombat to give learners the feeling of wizardly power at their fingertips by using typed code. If you want to learn to program, you need to write (a lot of) code. At CodeCombat, our job is to make sure you’re doing that with a smile on your face. Our courses have been specifically playtested to excel in the classroom, even by teachers with little to no prior programming experience.
Where to find it: