The download()
function of the downloads
API downloads a file, given its URL and other optional preferences.
- If the specified
url
uses the HTTP or HTTPS protocol, then the request will include all cookies currently set for its hostname. - If both
filename
andsaveAs
are specified, then the Save As dialog will be displayed, pre-populated with the specifiedfilename
.
This is an asynchronous function that returns a Promise
.
Syntax
var downloading = browser.downloads.download( options // object )
Parameters
options
- An
object
specifying what file you wish to download, and any other preferences you wish to set concerning the download. It can contain the following properties: -
body
Optional- A
string
representing the post body of the request. conflictAction
Optional- A string representing the action you want taken if there is a filename conflict, as defined in the
downloads.FilenameConflictAction
type (defaults to "uniquify" when it is not specified). filename
Optional- A
string
representing a file path relative to the default downloads directory — this provides the location where you want the file to be saved, and what filename you want to use. Absolute paths, empty paths, and paths containing back-references (../
) will cause an error. If omitted, this value will default to the filename already given to the download file, and a location immediately inside the downloads directory. headers
Optional- An
array
ofobjects
representing extra HTTP headers to send with the request if the URL uses the HTTP[s] protocol. Each header is represented as a dictionary object containing the keysname
and eithervalue
orbinaryValue
, restricted to those allowed byXMLHttpRequest
. incognito
Optional- A
boolean
: if present and set to true, then associate this download with a private browsing session. This means that it will only appear in the download manager for any private windows that are currently open. method
Optional- A
string
representing the HTTP method to use if theurl
uses the HTTP[S] protocol. This may be either "GET" or "POST". saveAs
Optional-
A
boolean
that specifies whether to provide a file chooser dialog to allow the user to select a filename (true
), or not (false
).If this option is omitted, the browser will show the file chooser or not based on the general user preference for this behavior (in Firefox this preference is labeled "Always ask you where to save files" in about:preferences, or
browser.download.useDownloadDir
in about:config).Note: Firefox for Android raises an error if
saveAs
is set totrue
. The parameter is ignored whensaveAs
isfalse
or not included. url
- A
string
representing the URL to download.
Return value
A Promise
. If the download started successfully, the promise will be fulfilled with the id
of the new downloads.DownloadItem
. Otherwise the promise will be rejected with an error message.
If you use URL.createObjectURL() to download data created in JavaScript and you want to revoke the object URL (with revokeObjectURL) later (as it is strongly recommend), you need to do that after the download has been completed. To do so, listen to the downloads.onChanged event.
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | ||||
---|---|---|---|---|---|
Basic support | Chrome Full support Yes | Edge No support No | Firefox Full support 47 | Opera Full support Yes | Firefox Android Full support 48 |
body | Chrome Full support Yes | Edge No support No | Firefox Full support 52 | Opera Full support Yes | Firefox Android Full support 52 |
conflictAction | Chrome Full support Yes | Edge No support No | Firefox Full support 47 | Opera Full support Yes | Firefox Android Full support 48 |
filename | Chrome Full support Yes | Edge No support No | Firefox Full support 47 | Opera Full support Yes | Firefox Android Full support 48 |
headers | Chrome Full support Yes | Edge No support No | Firefox Full support 47 | Opera Full support Yes | Firefox Android Full support 48 |
incognito | Chrome No support No | Edge No support No | Firefox Full support 57 | Opera No support No | Firefox Android Full support 57 |
method | Chrome Full support Yes | Edge No support No | Firefox
Full support
47
| Opera Full support Yes | Firefox Android
Full support
48
|
saveAs | Chrome Full support Yes | Edge No support No | Firefox
Full support
52
| Opera Full support Yes | Firefox Android No support No |
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.
- See implementation notes.
Examples
The following snippet attempts to download an example file, also specifying a filename and location to save it in, and the uniquify
conflictAction
option.
function onStartedDownload(id) { console.log(`Started downloading: ${id}`); } function onFailed(error) { console.log(`Download failed: ${error}`); } var downloadUrl = "https://example.org/image.png"; var downloading = browser.downloads.download({ url : downloadUrl, filename : 'my-image-again.png', conflictAction : 'uniquify' }); downloading.then(onStartedDownload, onFailed);
This API is based on Chromium's chrome.downloads
API.
// Copyright 2015 The Chromium Authors. All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following disclaimer // in the documentation and/or other materials provided with the // distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.