defer attribute for external scripts

- LS

The boolean defer attribute on script elements allows the external JavaScript file to run when the DOM is loaded, without delaying page load first.

Chrome

  1. 4 - 7: Not supported
  2. 8 - 125: Supported
  3. 126: Supported
  4. 127 - 129: Supported

Edge

  1. 12 - 124: Supported
  2. 125: Supported

Safari

  1. 3.1 - 4: Not supported
  2. 5 - 17.4: Supported
  3. 17.5: Supported
  4. 17.6 - TP: Supported

Firefox

  1. 2 - 3: Not supported
  2. 3.5 - 30: Supported
  3. 31 - 126: Supported
  4. 127: Supported
  5. 128 - 130: Supported

Opera

  1. 9 - 12.1: Not supported
  2. 15 - 109: Supported
  3. 110: Supported

IE

  1. 5.5 - 9: Partial support
  2. 10: Supported
  3. 11: Supported

Chrome for Android

  1. 125: Supported

Safari on iOS

  1. 3.2 - 4.3: Not supported
  2. 5 - 17.4: Supported
  3. 17.5: Supported
  4. 17.6 - 18.0: Supported

Samsung Internet

  1. 4 - 24: Supported
  2. 25: 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. 125: Supported

Firefox for Android

  1. 126: 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
WebPlatform Docs
async vs defer attributes