7–9 November 2016: Conference & Tutorials
9–10 November 2016: Training
Amsterdam, The Netherlands

On preloads and preloaders

Yoav Weiss (Akamai)
11:50–12:30 Monday, 7/11/2016
UX performance Mobile, Networking G102/103 Audience level: Intermediate
Average rating: ****.
(4.33, 18 ratings)

Prerequisite knowledge

  • Familiarity with web development concepts

What you'll learn

  • Learn how browsers load resources in order to avoid getting in their way
  • Understand the new standard techniques that can help the browser discover resources early as well as other interesting resource loading patterns


Parsing HTML in order to load a full web page is a complex process. On the one hand the browser needs to discover external resources as soon as possible. On the other hand, those same resources can in some cases block the browser’s HTML parser, as it may change the eventual result. Over the years, developers have implemented mechanisms in browsers to cope with this issue and ensure that resources are discovered even if the parser is blocked.

Yoav Weiss discusses these mechanisms and recent development efforts in the area and shares ways that developers can help the browser discover resources. Yoav then explores “link rel=preload”, a new link relation that can help us improve the browser’s resource discovery process, create various interesting new resource loading patterns, and get us faster-loading web pages.

Photo of Yoav Weiss

Yoav Weiss


Yoav Weiss is a principal architect at Akamai, where he focuses on making the web platform faster by adding performance-related features to browsers as well as to Akamai’s CDN. Yoav has been working on mobile web performance for longer than he cares to admit. He takes image bloat on the web as a personal insult, which is why he joined the Responsive Image community group and implemented the various responsive images features in Blink and WebKit. When he’s not writing code, he’s probably slapping his bass, mowing the lawn in the French countryside, or playing board games with his family.