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

Sites with Promise resolution microtasks Long Animation Frame (LoAF) script invoker type have a good INP most often: 99%, against 98% of all WordPress sites. Sites with ES module evaluation LoAF invokers have it least often, at 98%.

Timer and rAF callbacks is the most used: 40.7% of WordPress sites. Promise resolution microtasks is 0.5% of WordPress sites.

On jQuery, 41% of sites use timer and rAF callbacks Long Animation Frame (LoAF) script invoker type, and 98% of jQuery sites have a good INP, against 98% of all sites. On Vue, 48% of sites use timer and rAF callbacks, and 97% 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%98%

React 1,334 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 43%Classic <script> evaluation 38%DOM event listener (click / scroll / input) 35%98%

jQuery 32,959 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 41%Classic <script> evaluation 39%DOM event listener (click / scroll / input) 36%98%

Vue 2,694 sitesTimer / rAF callback (setTimeout / requestAnimationFrame) 48%DOM event listener (click / scroll / input) 33%Classic <script> evaluation 30%97%

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 Promise resolution microtasks Long Animation Frame (LoAF) script invoker type have a good INP, against 98% of jQuery sites with timer and rAF callbacks. Within jQuery, sites with Promise resolution microtasks and timer and rAF callbacks have a good INP about equally often. On Vue, 97% of sites with timer and rAF callbacks Long Animation Frame (LoAF) script invoker type have a good INP, against 98% of Vue sites with classic script evaluation. Within Vue, sites with timer and rAF callbacks and classic script evaluation 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 (98% good INP, 87ms median). Classic script evaluation accounts for 38.6% (98% good INP) and timer/rAF user-callbacks account for 40.7% (98% good INP), while heavy module-script evaluation (0.5%) and unbatched Promise microtasks (0.5%) drop to 98% and 99% good INP.