- Double check your spelling - its common to make a mistake with the camelCasing, which will case errors.
- Inspect the squares (if you only have one, go back to step 1 ), once the developer tools are open, open the console. There are already a lot of errors in the console due to the iframe. Scroll to the bottom and look for the “Uncaught” errors - these errors refer to issues that are being caused in the code.
Errors have been placed on purpose to get you to use the console. You have to fix the code according to the errors.