• Filters:
• Newly available
• Widely available
• Limited availability
• One missing engine
• Discouraged
• Opposed
• All features

• Features only in:
• Chromium
• Firefox
• Safari

• Browser releases:
• Chrome
• Chrome Android
• Edge 146
• Firefox 149
• Firefox for Android 149
• Safari 26.4
• Safari on iOS 26.4

New features in Safari 26.4 (released on 2026-03-24)

• Iterator.concat()

  Baseline Newly Available (since 2026-03-24)

  The Iterator.concat() JavaScript method returns an iterator that yields values from a sequence of iterators, exhausting each iterator before moving on to the next.

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  • Chrome 146 Released on 2026-03-10
  • Chrome Android 146 Released on 2026-03-10
  • Edge 146 Released on 2026-03-13
  • Firefox 147 Released on 2026-01-13
  • Firefox for Android 147 Released on 2026-01-13
  • Safari 26.4 Released on 2026-03-24
  • Safari on iOS 26.4 Released on 2026-03-24

• Readable byte streams

  Baseline Newly Available (since 2026-03-24)

  A ReadableStream constructed with { type: "bytes" } reads bytes from a stream without making extra copies, improving efficiency for streams of large chunks. Also known as BYOB or bring your own buffer.

  Learn more

  • Chrome 89 Released on 2021-03-02
  • Chrome Android 89 Released on 2021-03-02
  • Edge 89 Released on 2021-03-04
  • Firefox 102 Released on 2022-06-28
  • Firefox for Android 102 Released on 2022-06-28
  • Safari 26.4 Released on 2026-03-24
  • Safari on iOS 26.4 Released on 2026-03-24

• WebTransport

  Baseline Newly Available (since 2026-03-24)

  The WebTransport API transmits data between a client and a server, by using the HTTP/3 protocol.

  Learn more

  • Chrome 97 Released on 2022-01-04
  • Chrome Android 97 Released on 2022-01-04
  • Edge 97 Released on 2022-01-06
  • Firefox 114 Released on 2023-06-06
  • Firefox for Android 114 Released on 2023-06-06
  • Safari 26.4 Released on 2026-03-24
  • Safari on iOS 26.4 Released on 2026-03-24