URL: createObjectURL() static method
Note: This feature is available in Web Workers, except for Service Workers.
The createObjectURL()
static method of the URL
interface
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()
.
Note: This feature is not available in Service Workers due to its potential to create memory leaks.
Syntax
URL.createObjectURL(object)
Parameters
object
-
A
File
,Blob
, orMediaSource
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
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 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
<video>
element required creating an object URL for the
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 srcObject
to the MediaStream
directly.
Specifications
Specification |
---|
File API # dfn-createObjectURL |
Browser compatibility
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