JavaScript is the scripting language of the web. It provides rich interactivity and dynamic content for web applications. With it, you can build user experiences that can help users accomplish complex tasks, store user data, and more. Here, you can peruse our collection of JavaScript content and learn a variety of concepts and techniques to help you improve your JavaScript skills.

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If you're new to JavaScript, we've got you covered. Our Learn JavaScript course teaches the ins and outs of JavaScript, helping you to get up to speed.
Learn about the latest JavaScript features that are newly available in all major browser engines.
JavaScript provides many features to help you build applications that respond to the needs of your users.
Interaction to Next Paint (INP) is an important responsiveness metric that measures page responsiveness. These guides contain JavaScript tips to help you keep your pages responsive to users.
Third-party JavaScript can be a cause of performance issues in web applications. Learn how to manage third-party scripts to keep your web applications fast.
Check out these JavaScript patterns you can use to quickly accomplish common tasks in your web applications.
COURSE

If you're new to JavaScript, we've got you covered. Our Learn JavaScript course guides you through how JavaScript works, beginning with the basics such as variables, functions, and conditional statements. From there, you'll tackle more complex topics such as prototypal inheritance, classes, and other topics to help you hone your JavaScript skills so that you can build rich web applications.

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Baseline signals to web developers when web platform features can be safely used in all major browser engines. Here are some JavaScript features that are now Baseline Newly available.
Promise.try() became Baseline Newly available in January 2025.
Resizable ArrayBuffer became Baseline Newly available in July 2024.
Set methods became Baseline Newly available in June 2024.
CustomStateSet became Baseline Newly available in May 2024.
The Screen Wake Lock API became Baseline Newly available in May 2024.
intl.Segmenter became Baseline Newly available in April 2024.
promise.withResolvers() became Baseline Newly available in March 2024.
groupBy() functions became Baseline Newly available in March 2024.
The ArrayBuffer transfer() and transferToFixedLength() methods became Baseline Newly available in March 2024.
Array.fromAsync() became Baseline Newly available in January 2024.

JavaScript gives you a lot of tools to help you build applications that respond to the needs of your users. Here are some common features might want to use in your web applications that are worth knowing about!
Promises allow you to asynchronously execute code after a certain event occurs.
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The fetch API allows you to make HTTP requests to fetch data from the web on the front end.
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The IndexedDB API offers client-side storage of structured data, including files and blobs.
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How you use JavaScript can have an effect on your web application's Interaction to Next Paint (INP). These guides will help you to get a handle on page repsonsiveness issues caused by JavaScript.

Long tasks on the main thread can cause your web application to be unresponsive. Learn how to optimize long tasks to improve your web application's INP.
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Long input delays occur when users interact with a page and the browser takes too long respond—and JavaScript can be a common culprit. Read this guide and learn how you can keep input delays shorter and your web application snappier.
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When scripts are downloaded during page load, they can cause long tasks that can affect your web application's INP. Learn how to optimize for long script evaluation tasks to keep your INP low.