Reference files for the live-coding demos, in teaching order. Open any example and use View Source (right-click → View Page Source) to read the code — then rebuild it yourself.
▶ Open the Interactive SlidesquerySelector, getElementById
Content, styles, attributes
Click, input, form events
Complete DOM example
Tip: don't copy-paste. Type the code yourself, break it on purpose, then fix it. Use DevTools (F12) to inspect what's happening.