The Download Attribute

• Browser Compatibility
• Usage
• Tips

The download attribute is an attribute on <a> elements introduced in HTML5, which instructs browsers to download a URL instead of navigating to it.

Browser Compatibility

As to the compatibility of download attribute, it's supported by Chrome >=14 (2011-09), Firefox >=20 (2013-04), Edge 13 (2015-11), but has no support in IE or Safari (supported in Safari Technology Preview).

One more note on Edge: support for download attribute in Edge is partial, i.e., the value (file name) set in download attribute is not considered.

See:

• https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#Browser_compatibility
• http://caniuse.com/#feat=download

Usage

If download attribute is set (whatever its value or no value), the link will get downloaded instead of being navigated to. This subjects to the same-origin policy in Firefox, but works in Chrome and Edge whether the target is of same-origin or not.

If download attribute has a value, it's used as the pre-filled file name when saving the target. Though this functionality is bound to the same-origin policy. That is to say, if the link target is not of same-origin, the value of download attribute (pre-filled file name) won't be considered.

If the provided file name in download attribute contains disallowed characters for the operating system, it will get substituted (with - in Chrome and _ in Firefox). And if no valid file name can be constructed, Chrome defaults the file name to download.

Tips

In Chrome, even if a link is downloaded instead of being navigated to (though technically speaking, it's navigated under the hood), Chrome will give a warning in Developer Tools if download attribute is not set. So always include this if link target is supposed to be downloaded, and make this a best practice. As this won't hurt for browsers do not support it anyway.

And the situation is similar for Edge, even if a link can be downloaded without download attribute, Edge will give warnings in Developer Tools. So just include the download attribute for files intended to be downloaded.