Mdn download file

It returns a promise that resolves with an ArrayBuffer. File Returns a newly constructed File. File implements Blob , so it also has the following properties available to it: File. The File interface doesn't define any methods, but inherits methods from the Blob interface: Blob.

File API file-section. This enables the garbage collector to free the memory allocated to the URL. If this is not done, the memory will not get returned until the page on which it was created is closed.

Once the blob URL has been revoked, any attempt to load it will result in an error. For example, if the blob url was used as the SRC attribute of an IMG tag, the image will not load and will not be visible. Where you have a native app or want to deliver additional native features for file processing, use native messaging to pass a file to a native app for processing.

Here you trigger the process with runtime. Port object. Using the onMessage. The native application is opened if it is not running when runtime. Here you use runtime. The browser closes the native application after receiving any message back from the native application. To add the file or blob you want the native application to process use JSON. To use this method the extension must request the "nativeMessaging" permission or optional permission in its manifest.

Where optional permission is used, remember to check that permission has being granted and where necessary request permission from the user with the permissions API. Opening files using a file picker on a web page. When set to:. 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. The cookie store ID of the contextual identity the download is associated with. If omitted, the default cookie store is used. Use requires the "cookies" API permission. 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. If omitted, this value will default to the filename already given to the download file, and a location immediately inside the downloads directory.

Each header is represented as a dictionary object containing the keys name and either value or binaryValue. The headers that are forbidden by XMLHttpRequest and fetch cannot be specified, however, Firefox 70 and later enables the use of the Referer header.

Attempting to use a forbidden header throws an error. A boolean : if present and set to true, then associate this download with a private browsing session.