MDN Web Docs @MozDevNet

The official MDN Web Docs account. We deliver the best web docs around. developer.mozilla.org Worldwide Joined March 2013

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MDN Web Docs @MozDevNet

16 hours ago

Style text selections with ::highlight! The ::highlight pseudo-element lets you customize how text highlights appear. Not just for user selection (::selection), but also for custom highlights created via the Highlight API Learn more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

2 days ago

Tired of long-running scripts blocking the UI? The Web Workers API lets you run JS in the background, keeping your app responsive and smooth. ✅ Offload heavy tasks ✅ Keep the main thread free ✅ Great for data crunching, parsing, and more Read how 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

3 days ago

🕵️‍♂️ The User-Agent HTTP header tells the server what client is making the request, like browser, OS, and rendering engine. It helps servers: ✅ Serve browser-specific content ✅ Log usage patterns ❌ But can also be a source of fingerprinting Read more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

4 days ago

What does the k1 attribute do in SVG? 🌀 The k1 attribute is used with the <feConvolveMatrix> filter element in SVG to apply convolution effects. It’s part of the kernel matrix that defines how pixels are transformed. Learn more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

4 days ago

🧪 Thinking of using fetch() streams to track upload/download progress? @jaffathecake shares more, and how could limit future browser optimizations. ✅ Streams = Great for parallel processing ❌ Streams ≠ Reliable for measuring up/down % Read more 👇 jakearchibald.com/2025/fetch-str…

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MDN Web Docs @MozDevNet

5 days ago

Guide assistive tech with aria-orientation 🧭 The aria-orientation attribute helps screen readers and other assistive tech understand how a UI component is laid out, horizontal or vertical, with widgets like ↕️ Sliders ↔️ Tabs 🔼 Treeviews Read more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

a week ago

Tired of hacking together deep copies with JSON.parse(JSON.stringify(...))? 🔁 The structuredClone() method lets you safely clone complex JavaScript objects. No data loss. No surprises. Just clean, reliable cloning. Learn more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

a week ago

We’d love your feedback! 📣 Take our quick 1–2 minute survey on using ReadableStream as a request body with the Fetch API. Your input helps shape browser support and prioritize real-world use cases. Share your thoughts 📝 survey.alchemer.com/s3/8460326/Fet…

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Gabriel 🪶 @Gabixel_

a week ago

Such a nice little setting. Many people don't know how many attributes you can edit in a lot of fonts, for both accessibility and design choices

MDN Web Docs @MozDevNet

a week ago

Such a nice little setting. Many people don't know how many attributes you can edit in a lot of fonts, for both accessibility and design choices

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MDN Web Docs @MozDevNet

a week ago

Need your numbers to line up? Or prefer old-school serif-style numerals? CSS has a property for that: font-variant-numeric // font-variant-numeric: tabular-nums; ✅ Tabular vs proportional ✅ Lining vs oldstyle ✅ Even supports slashed zero Read more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

a week ago

Need to watch for DOM changes without running expensive polling logic? Use a MutationObserver, it tracks changes to elements in real time. ✅ Efficient ✅ Native ✅ Great for components that react to dynamic content How it works + what to observe 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

2 weeks ago

Simple, native, reliable. 📌 Relative URLs can be weird, but the URL API makes resolving them super clean. 🚫 Not string concat ✅ Real path resolution 📎 new URL() throws on bad input 📎 URL.parse() returns null instead Here's a breakdown 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

2 weeks ago

Did you share your opinion yet? 🤔 We're running a short survey (1–2 min) to understand interest in using ReadableStream as a request body in the Fetch API. Help us guide implementation priorities. Fill up the survey! 👇 survey.alchemer.com/s3/8460326/Fet…

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MDN Web Docs @MozDevNet

2 weeks ago

Need a Fetch refresher? ⛲ Fetch API offers cleaner, promise-based syntax, better error handling, and async/await support. You can: 🔒 Add tokens & content types 📮 Make POST requests 🚅 Manage large data sets efficiently Learn more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

2 weeks ago

Let's learn about CSP (Content Security Policy) 🛡️ CSP, when set properly, ✅ Blocks malicious scripts from running on your site. ✅ Prevents data injection attacks. ✅ Reduces the risk of clickjacking and other web security threats. Learn more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

2 weeks ago

We are looking for your input! 📣 We're running a short survey (1–2 min) to understand interest in using ReadableStream as a request body in the Fetch API. Help us guide implementation priorities, especially around support & use cases. Fill it up! 👇 survey.alchemer.com/s3/8460326/Fet…

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MDN Web Docs @MozDevNet

2 weeks ago

Did you know? 🤔 rel="me" was introduced in the XFN (XHTML Friends Network) spec in the early 2000s as part of a push for semantic relationships on the web. Browsers don’t do anything with it visually, crawlers and authentication systems can use it to verify online identity.

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MDN Web Docs @MozDevNet

2 weeks ago

Features from <select> you should know: ✅ disabled — prevent user interaction ✅ multiple — allow multi-select ✅ size — show more than one option at a time ✅ <optgroup> — group related options And there are more 👇 developer.mozilla.org/en-US/docs/Web…

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MDN Web Docs @MozDevNet

3 weeks ago

📣 Web devs — we need your input! We're running a short survey (1–2 min) to understand interest in using ReadableStream as a request body in the Fetch API. Help us guide implementation priorities, especially around support & use cases. Fill it up! 👇 survey.alchemer.com/s3/8460326/Fet…

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MDN Web Docs @MozDevNet

3 weeks ago

Meet the Cache API, your tool for storing request/response pairs in the browser! 🗂️ Part of the Service Worker ecosystem, it lets you: ✅ Store fetch responses for offline access ✅ Speed up repeat requests ✅ Build reliable PWAs Learn more 👇 developer.mozilla.org/en-US/docs/Web…