Defer/async scripts
Detects render-blocking <script> tags in <head> without defer or async.
¿Por qué importa esto?
Scripts without defer or async in the <head> block HTML parsing until they are fully loaded and executed. This delays First Contentful Paint (FCP) and can slow down the page by several seconds.
¿Cómo se soluciona?
Add defer to scripts that can execute after the DOM is loaded. Use async for scripts that are independent of the DOM (e.g. analytics). Move scripts before </body> if not possible.
Este check puntúa de 0 a 100. Bajo 50 es un fallo, 50 a 89 un aviso, 90 o más es bueno. Tras cada crawl ve la nota por página en el informe, con una breve explicación.
Preguntas frecuentes
Detects render-blocking <script> tags in <head> without defer or async.
Scripts without defer or async in the <head> block HTML parsing until they are fully loaded and executed. This delays First Contentful Paint (FCP) and can slow down the page by several seconds.
Add defer to scripts that can execute after the DOM is loaded. Use async for scripts that are independent of the DOM (e.g. analytics). Move scripts before </body> if not possible.
Ejemplo
Copie el código de abajo y adapte el dominio, la marca y el contenido a su situación.
<script src="app.js" defer></script>