async attribute for external scripts

- LS

The boolean async attribute on script elements allows the external JavaScript file to run when it's available, without delaying page load first.

Chrome

  1. 4 - 7: Not supported
  2. 8 - 121: Supported
  3. 122: Supported
  4. 123 - 125: Supported

Edge

  1. 12 - 121: Supported
  2. 122: Supported

Safari

  1. 3.1 - 4: Not supported
  2. 5: Partial support
  3. 5.1 - 17.3: Supported
  4. 17.4: Supported
  5. TP: Supported

Firefox

  1. 2 - 3.5: Not supported
  2. 3.6 - 122: Supported
  3. 123: Supported
  4. 124 - 126: Supported

Opera

  1. 9 - 12.1: Not supported
  2. 15 - 107: Supported
  3. 108: Supported

IE

  1. 5.5 - 9: Not supported
  2. 10: Supported
  3. 11: Supported

Chrome for Android

  1. 122: Supported

Safari on iOS

  1. 3.2 - 4.3: Not supported
  2. 5 - 17.3: Supported
  3. 17.4: Supported

Samsung Internet

  1. 4 - 22: Supported
  2. 23: Supported

Opera Mini

  1. all: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 80: Supported

UC Browser for Android

  1. 15.5: Supported

Android Browser

  1. 2.1 - 2.3: Not supported
  2. 3 - 4.4.4: Supported
  3. 122: Supported

Firefox for Android

  1. 123: Supported

QQ Browser

  1. 14.9: Supported

Baidu Browser

  1. 13.52: Supported

KaiOS Browser

  1. 2.5: Supported
  2. 3: Supported
Resources:
MDN Web Docs - Script attributes
has.js test
Demo
async vs defer attributes