WordPress Long Animation Frame (LoAF) script invokers and the Core Web Vitals

Sites with classic script evaluation Long Animation Frame (LoAF) script invoker type have a good INP most often: 100%, against 100% of all WordPress sites. Sites with DOM event listeners LoAF invokers have it least often, at 99%.

Timer and rAF callbacks is the most used: 40.7% of WordPress sites. Classic script evaluation is 38.6% of WordPress sites.

On jQuery, 41% of sites use timer and rAF callbacks Long Animation Frame (LoAF) script invoker type, and 100% of jQuery sites have a good INP, against 100% of all sites. On Vue, 48% of sites use timer and rAF callbacks, and 99% of Vue sites have a good INP.

FrameworkLong Animation Frame (LoAF) script invoker type on its sitesGood INP

WordPress sites with Long Animation Frame (LoAF) script invoker type 34,005 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 41%Classic <script> evaluation 39%DOM event listener (click / scroll / input) 36%100%

jQuery 32,959 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 41%Classic <script> evaluation 39%DOM event listener (click / scroll / input) 36%100%

React 1,334 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 43%Classic <script> evaluation 38%DOM event listener (click / scroll / input) 35%100%

Vue 2,694 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 48%DOM event listener (click / scroll / input) 33%Classic <script> evaluation 30%99%

Timer / rAF callback (setTimeout / requestAnimationFrame) Classic <script> evaluation DOM event listener (click / scroll / input) Promise microtask resolution (then / async-await) ES module <script type="module"> evaluation

Does the framework explain the Long Animation Frame (LoAF) script invoker type difference?

On jQuery, 100% of sites with classic script evaluation Long Animation Frame (LoAF) script invoker type have a good INP, against 100% of jQuery sites with timer and rAF callbacks. Within jQuery, sites with classic script evaluation and timer and rAF callbacks have a good INP about equally often. On Vue, 100% of sites with classic script evaluation Long Animation Frame (LoAF) script invoker type have a good INP, against 100% of Vue sites with timer and rAF callbacks. Within Vue, sites with classic script evaluation and timer and rAF callbacks have a good INP about equally often.

What triggers main-thread Long Animation Frames during load and interaction

The Long Animation Frames API (LoAF) attributes every frame over 50ms to the exact invoker that started the script task. Across 12,267 sites (36.1% of LoAF sites), DOM event listeners trigger long frames (99% good INP, 49ms median). Classic script evaluation accounts for 38.6% (100% good INP) and timer/rAF user-callbacks account for 40.7% (100% good INP), while heavy module-script evaluation (0.5%) and unbatched Promise microtasks (0.5%) drop to 100% and 98% good INP.