HTML5 JS API Index > File API Tutorials & Specs
Extended by File
This interface represents immutable raw data. It provides a method to slice data objects between ranges of bytes into further chunks of raw data. It also provides an attribute representing the size of the chunk of data. The File interface inherits from this interface.
|unsigned long long|
- Returns the size of the Blob object in bytes. On getting, conforming user agents must return the total
number of bytes that can be read by a FileReader or FileReaderSync object, or 0 if the
Blob has no bytes to be read. If the Blob has been neutered with close called on it, then size must return 0.
- The ASCII-encoded string in lower case representing the media type of the Blob. For File objects that are returned from the underlying file system, user agents must return the type of a Blob as an ASCII-encoded string in lower case, such that when it is converted to a corresponding byte sequence, it is a parsable MIME type [MIMESNIFF], or the empty string -- 0 bytes -- if the type cannot be determined.
- Calling the close method must permanently neuter the original Blob object. This is an irreversible and non-idempotent operation; once a Blob has been neutered, it cannot be used again; dereferencing a Blob URL bound to a Blob object on which close has been called results in a network error.
- slice(optional long long start, optional long long end, optional DOMString contentType)
- The slice method returns a new Blob object with bytes ranging from the optional start
parameter upto but not including the optional end parameter, and with a
type attribute that is the value of the optional contentType parameter.