2 docs tagged with "defer"

Understand what a browser does when it meets a script, why JavaScript is the most expensive kind of file, and how to load it without blocking the page. Includes a script order lab and a script weight lab.

Learn exactly how the defer attribute works: when deferred scripts download and run, what order they keep, which bugs appear when you add it, and how to move an old page to defer safely. Includes a run order simulator and a migration helper.