Performance and cache plugins

What loads, and when#

• Foliora's scripts load only on pages that contain a viewer.
• PDF.js 3.11.174 is bundled — no CDN request, no DNS lookup to another host.
• With lazy loading, a viewer starts only when it is about to scroll into view. Turn it on site-wide in Settings → Viewer defaults or per embed with loading="lazy".
• Only the visible page (or spread) is drawn; scroll view draws the pages near the screen.

Cache and optimisation plugins#

Minifying, combining or delaying PDF.js breaks it. Foliora excludes its scripts automatically in:

The script tags are also marked data-no-optimize. If another optimiser still bundles them, add these to its exclusion list:

foliora-viewer.js
pdf.min.js
pdf.worker.min.js

Large files#

• The PDF is downloaded once per visit (then served from the browser cache). Compress large PDFs — “Reduce file size” in Acrobat, or export with web-optimised settings.
• Split very long documents into chapters and link them.
• Images inside the PDF are the usual cause of size; 150 dpi is plenty for screens.