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defer attribute for external scripts

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

Last updated on : 2023-03-20

Browser Versions

Edge

Firefox

Chrome

Safari

Opera

5.5 - 9

10 - 11

12 - 111

2 - 3

3.6 - 113

4 - 7

8 - 114

3.2 - 4

5.1 - 16.4

9.5 - 12.1

15 - 95

Fully Supported

Partially

No Support

Specifications

HTML Standard # the-script-element

Browser Compatibility

defer attribute for external scripts on IE is fully supported on 10-11 and partially supported on 5.5-9 IE versions.

defer attribute for external scripts on Edge is fully supported on all Edge versions.

defer attribute for external scripts on Firefox is fully supported on 3.6-113, and not supported on 2-3 Firefox versions.

defer attribute for external scripts on Chrome is fully supported on 8-114, and not supported on 4-7 Chrome versions.

defer attribute for external scripts on Safari is fully supported on 5.1-16.4, and not supported on 3.2-4 Safari versions.

defer attribute for external scripts on Opera is fully supported on 15-95, and not supported on 9.5-12.1 Opera versions.

defer attribute for external scripts on Safari on iOS is fully supported on 5-16.4, and not supported on 3.2-4 Safari on iOS versions.

defer attribute for external scripts on Android Browser is fully supported on 3-111, and not supported on 2.1-2.2 Android Browser versions.

defer attribute for external scripts on Opera Mobile is fully supported on 64-73, and not supported on 10-12 Opera Mobile versions.

defer attribute for external scripts on Chrome for Android is fully supported on all Chrome for Android versions.

defer attribute for external scripts on Firefox for Android is fully supported on all Firefox for Android versions.

defer attribute for external scripts on Samsung Internet is fully supported on all Samsung Internet versions.

Browser Support for defer attribute for external scripts

defer attribute for external scripts on Chrome

defer attribute for external scripts on Safari

defer attribute for external scripts on Firefox

defer attribute for external scripts on Internet Explorer

defer attribute for external scripts on Opera

defer attribute for external scripts on Edge

References

Data sourced from

100

High

Overall Browser Compatibility Score

Note:defer attribute for external scripts shows a browser compatibility score of 100. This is a collective score out of 100 to represent browser support of a web technology. The higher this score is, the greater is the browser compatibility. The browser compatibility score is not a 100% reflection for every browser and the web technology support. However, it does give you an estimate on how much you should rely on a particular web technology in terms of browser compatibility.

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