Can I use defer attribute for external scripts?

Compatibility table for support of defer attribute for external scripts in desktop and mobile browsers.

Legend

defer attribute for external scripts

- CR

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

IE

  1. 5.5
  2. 6
  3. 7
  4. 8
  5. 9
  6. 10
  7. 11

Firefox

  1. 2
  2. 3
  3. 3.5
  4. 3.6
  5. 4
  6. 5
  7. 6
  8. 7
  9. 8
  10. 9
  11. 10
  12. 11
  13. 12
  14. 13
  15. 14
  16. 15
  17. 16
  18. 17
  19. 18
  20. 19
  21. 20
  22. 21
  23. 22
  24. 23
  25. 24
  26. 25
  27. 26
  28. 27
  29. 28
  30. 29
  31. 30
  32. 31
  33. 32
  34. 33
  35. 34

Chrome

  1. 4
  2. 5
  3. 6
  4. 7
  5. 8
  6. 9
  7. 10
  8. 11
  9. 12
  10. 13
  11. 14
  12. 15
  13. 16
  14. 17
  15. 18
  16. 19
  17. 20
  18. 21
  19. 22
  20. 23
  21. 24
  22. 25
  23. 26
  24. 27
  25. 28
  26. 29
  27. 30
  28. 31
  29. 32
  30. 33
  31. 34
  32. 35
  33. 36
  34. 37
  35. 38
  36. 39

Safari

  1. 3.1
  2. 3.2
  3. 4
  4. 5
  5. 5.1
  6. 6
  7. 6.1
  8. 7
  9. 8

Opera

  1. 9
  2. 9.5-9.6
  3. 10.0-10.1
  4. 10.5
  5. 10.6
  6. 11
  7. 11.1
  8. 11.5
  9. 11.6
  10. 12
  11. 12.1
  12. 15
  13. 16
  14. 17
  15. 18
  16. 19
  17. 20
  18. 21
  19. 22
  20. 23
  21. 24

iOS Safari

  1. 3.2
  2. 4.0-4.1
  3. 4.2-4.3
  4. 5.0-5.1
  5. 6.0-6.1
  6. 7.0-7.1
  7. 8

Opera Mini

  1. 5.0-7.0

Android Browser

  1. 2.1
  2. 2.2
  3. 2.3
  4. 3
  5. 4
  6. 4.1
  7. 4.2-4.3
  8. 4.4
  9. 4.4.3

Blackberry Browser

  1. 7
  2. 10

Opera Mobile

  1. 10
  2. 11
  3. 11.1
  4. 11.5
  5. 12
  6. 12.1
  7. 22

Chrome for Android

  1. 35

Firefox for Android

  1. 30

IE Mobile

  1. 10

Partial support refers to a buggy implementation in IE<10

Resources:
WebPlatform Docs
MDN article
has.js test

*Global usage share statistics based on data from StatCounter GlobalStats for June, 2014. See the browser usage table for usage by browser version.