Zinn® Cache: Remove unused CSS, delay JavaScript and serve WebP and AVIF

Remove unused CSS, delay JavaScript and serve WebP and AVIF

Use Zinn® Cache Pro's CSS and JavaScript tab to remove unused CSS and delay scripts, and its Images tab for WebP, AVIF and missing image sizes — why there is no minify or combine option, and how to undo a change that breaks a page.

1. Test one change at a time — Asset optimisation changes how the browser receives your theme's files. Change one setting, check the site, then move on, so a problem has an obvious cause.
2. Open the CSS and JavaScript tab — In WordPress open Zinn Digital®, Cache Pro, then CSS and JavaScript. Images are on their own tab.
3. Start with the safe defaults — Keep Use the safe defaults on. It never delays jQuery or cookie-consent banners and leaves checkout pages alone.
4. Delay JavaScript, then remove unused CSS — Turn on Delay JavaScript until the visitor interacts, save and check your key pages signed out. Then turn on Remove unused CSS. If something stops working, add its script or stylesheet to the list of files to leave alone.
5. Serve WebP and AVIF images — On the Images tab turn on WebP or AVIF, then convert your existing images. The originals stay where they are, and one click removes every converted copy.
6. Why there is no minify or combine option — Combining files helped on HTTP/1.1 but slows pages on HTTP/2 and HTTP/3, and minifying saves a few percent once files are compressed while being the most common cause of a broken layout. Removing unused CSS and delaying JavaScript is where the real gain is.

With screenshots: https://zinncache.com/kb/minify-css-and-javascript-in-wordpress