The FileReader
object lets web applications asynchronously read the contents of files (or raw data buffers) stored on the user's computer, using File
or Blob
objects to specify the file or data to read.
File objects may be obtained from a FileList
object returned as a result of a user selecting files using the <input>
element, or from a drag and drop operation's DataTransfer
object.
FileReader
can only access the contents of files that the user has explicitly selected, either using an HTML <input type="file">
element or by drag and drop. It cannot be used to read a file by pathname from the user's file system. To read files on the client's file system by pathname, use the File System Access API. To read server-side files, use standard Ajax solutions, with CORS permission if reading cross-domain.
Note: This feature is available in Web Workers