Pick a Python lab and re-do it in JavaScript. You should first try to write them using JavaScript's prompt and alert in place of Python's input and print.
- Random Password Generator
- Rock, Paper, Scissors
- Unit Converter
- Credit Card Validation
- Rot13
- Number to Phrase
Once you have that working, use input and button elements, with events. You can read the docs on DOM Manipulation and Events. You can view a demo here.