How to Properly Defer JavaScript in WordPress

Originally published at https://makewpfast.com/how-to-properly-defer-javascript-in-wordpress/ Render-blocking JavaScript is one of the most common performance issues flagged by PageSpeed Insights and Core Web Vitals. When a browser encounters a script tag, it stops rendering the page until that script is downloaded and executed. Deferring scripts tells the browser to continue rendering while downloading scripts in the background. defer vs async: Know the Difference Both attributes load scripts without blocking rendering, but they behave differently: defer — Downloads in parallel, executes after HTML parsing is complete, maintains execution order async — Downloads in parallel, executes immediately when ready, no guaranteed order For most WordPress scripts, defer is the safer choice because plugins often depend on execution order (jQuery first, then dependent scripts). Adding defer in WordPress (The Right Way) Since WordPress 6.3, you can use the built-in wp_script_add_data() approach or