Cannot run code in JavaScript lessons

I have been trying to complete the “Increment a Number with JavaScript” lesson and whenever I hit the run code button the button changes color but outside of that nothing happens. I’ve used Firefox, Google Chrome,Opera and even tried to finish it on my iPhone and nothing has worked so far.

Not sure what to do at this point

What is your code?

I am on my phone or I would copy and paste it but the lesson wants you to replicate myVar+1 using myVar++ so the only code I added was the 2 plus signs next to myVar