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4 documents tagged with “Long Tasks”

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A long task is a piece of JavaScript that runs on the main thread for longer than 50 ms and blocks everything else for that time. The user clicks, but the page does not respond. INP shoots up, Lighthouse flags it in the report.

Under the long tasks tag you will find articles on finding them in devtools, which techniques help (yield, scheduler.postTask, debouncing), and when it makes sense to refactor a larger piece of code.

JS Long Tasks (JSLT) Metric: When Your Website Forgets to Breathe

We will explain how the JS Long Tasks metric measures digital gridlocks in the form of long tasks and what these gridlocks can mean for your users and your business.

PageSpeed.ONE Study: The Impact of Chat Widgets on Website Speed

Live chat is used by twenty percent of Czech e-shop operators. But how do these components affect website speed?

setTimeout: Optimising Long Tasks in JS

The setTimeout() method is used to optimise long tasks in JavaScript that block user interactions, thereby affecting metrics like Total Blocking Time (TBT) or Interaction to Next Paint (INP), an essential part of the Core Web Vitals set.

The “Total Blocking Time” (TBT) Metric

Total Blocking Time (TBT) is a web performance metric that indicates the total duration during which a rendered page is unable to respond to user inputs.

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