URL: createObjectURL() static method

{{APIRef("File API")}}  {{AvailableInWorkers("window_and_worker_except_service")}} 

The createObjectURL() static method of the {{domxref("URL")}}  interface creates a string containing a URL representing the object given in the parameter.

The URL lifetime is tied to the {{domxref("document")}}  in the window on which it was created. The new object URL represents the specified {{domxref("File")}}  object or {{domxref("Blob")}}  object.

To release an object URL, call {{domxref("URL.revokeObjectURL_static", "revokeObjectURL()")}} .

[!NOTE] This feature is not available in Service Workers due to its potential to create memory leaks.

Syntax

URL.createObjectURL(object)

Parameters

• object
  • : A {{domxref("File")}} , {{domxref("Blob")}} , or {{domxref("MediaSource")}}  object to create an object URL for.

Return value

A string containing an object URL that can be used to reference the contents of the specified source object.

Examples

See Using object URLs to display images.

Usage notes

Memory management

Each time you call createObjectURL(), a new object URL is created, even if you’ve already created one for the same object. Each of these must be released by calling {{domxref("URL.revokeObjectURL_static", "URL.revokeObjectURL()")}}  when you no longer need them.

Browsers will release object URLs automatically when the document is unloaded; however, for optimal performance and memory usage, if there are safe times when you can explicitly unload them, you should do so.

Using object URLs for media streams

In older versions of the Media Source specification, attaching a stream to a {{HTMLElement("video")}}  element required creating an object URL for the {{domxref("MediaStream")}} . This is no longer necessary, and browsers are removing support for doing this.

[!WARNING] If you still have code that relies on createObjectURL() to attach streams to media elements, you need to update your code to set {{domxref("HTMLMediaElement.srcObject", "srcObject")}}  to the MediaStream directly.

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• Using files from web applications
• Using object URLs to display images
• {{domxref("URL.revokeObjectURL_static", "URL.revokeObjectURL()")}} 
• {{domxref("HTMLMediaElement.srcObject")}} 
• {{domxref("FileReader.readAsDataURL()")}}