Languages
Web APIs
Published articles in Languages / Web APIs.
More articles in this area
Async and defer loading of JavaScript
Classic script tags block HTML parsing while they download and run. The async and defer attributes change when download and execution happen relative to the document, and module scripts follow different rules again.
Observing element changes with MutationObserver in JavaScript
MutationObserver runs a callback after the DOM changes — attributes, child nodes, or text — without polling. This page shows how to configure observation narrowly so you pay only for the mutations you care about.