Thanks to Seafra and a great tip!

A really big thank-you to Seafra for visiting our DoJo yesterday evening. His software presentation was really impressive. I didn’t realise that he had written the physics engine himself. Now that’s cool.
He also showed me something with NotePad++ that will speed up your development. Once you’ve made a code change in NotePad++ and saved, you can go to the Run menu and select Launch in Firefox etc. to open the file in the browser. Great tip!