Stephen and Chris hop on to talk about how we’re saving everyone from crashed browser tabs in CodePen’s 2.0 editor. One simple:

while ( true ) { } Code language: JavaScript ( javascript )

Executing JavaScript can cause a browser tab to entirely lock up, preventing you from doing anything, like potentially saving your work. It can even crash other same-domain tabs. But not on our watch! CodePen is now using a “heartbeat” technique to report up from the preview iframe to the parent page, and if we don’t hear the heartbeat, we can rip out the iframe and stop the crash.…