File.getAsBinary() - Web APIs 编辑

Non-standard

This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Obsolete since Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4)

This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

Summary

The getAsBinary method allows to access the file's data in raw binary format.

Note: This method is obsolete; you should use the FileReader method readAsBinaryString() or readAsArrayBuffer() instead.

Syntax

var binary = instanceOfFile.getAsBinary();

Returns

A string.

Example

// fileInput is an HTMLInputElement: <input type="file" id="myfileinput" multiple>
var fileInput = document.getElementById("myfileinput");

// files is a FileList object (similar to NodeList)
var files = fileInput.files;

// object for allowed media types
var accept = {
  binary : ["image/png", "image/jpeg"],
  text   : ["text/plain", "text/css", "application/xml", "text/html"]
};

var file;

for (var i = 0; i < files.length; i++) {
  file = files[i];

  // if file type could be detected
  if (file !== null) {
    if (accept.binary.indexOf(file.type) > -1) {
      // file is a binary, which we accept
      var data = file.getAsBinary();
    } else if (accept.text.indexOf(file.type) > -1) {
      // file is of type text, which we accept
      var data = file.getAsText();
      // modify data with string methods
    }
  }
}

Specifications

Not part of any specification.

See also

• File
• FileReader