WHAT WAS THE MOST GENIUS HACK YOU DID IN WEBDEV? (REDDIT THREAD)

Summary from the TLDR Web Dev newsletter

Developers share their web dev “hacks” and stories. One developer improved a slow SQL scheduling algorithm by refactoring the code and converting sub-selects to joins. Others found creative ways to work around limitations in older web tech, like using system commands for a school prank or inventing a precursor to AJAX for a chat application.