The URL.createObjectURL() static method creates a string containing a URL representing the object given in the parameter.

The URL lifetime is tied to the document in the window on which it was created. The new object URL represents the specified File object or Blob object.

To release an object URL, call revokeObjectURL().

object

A File, Blob, or MediaSource object to create an object URL for.

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

See Using object URLs to display images.

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 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.

In older versions of the Media Source specification, attaching a stream to a <video> element required creating an object URL for the MediaStream. This is no longer necessary, and browsers are removing support for doing this.

• Using files from web applications
• Using object URLs to display images
• URL.revokeObjectURL()
• HTMLMediaElement.srcObject
• FileReader.readAsDataURL()