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). 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.
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.
Chrome | Edge | Firefox | Firefox for Android | Opera | |
---|---|---|---|---|---|
Basic support | Yes | No | 47 | 48 | Yes |
body | Yes | No | 52 | 52 | Yes |
conflictAction | Yes | No | 47 | 48 | Yes |
filename | Yes | No | 47 | 48 | Yes |
headers | Yes | No | 47 | 48 | Yes |
incognito | No | No | 57 | 57 | No |
method | Yes | No | 471 | 481 | Yes |
saveAs | Yes | No | 522 | 522 | Yes |
1. POST is supported from version 52.
2. Before version 58, if this option was omitted, Firefox would never show the file chooser, regardless of the value of the browser's preference.
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.
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