The obsolete XMLHttpRequest method sendAsBinary() is a variant of the send() method that sends binary data. The send() method now supports binary data and should now be used instead.

This method makes it possible to read and upload any type of file and to stringify the raw data.

Warning: This method is obsolete and should not be used. You should instead use the send() method, which now supports binary data in various forms.




A DOMString which encodes the binary content to be sent. You can create the binary string using the FileReader method readAsBinaryString(). The string is converted to binary for transfer by removing the high-order byte of each character.

Return value



Since sendAsBinary() is an experimental feature, here is a polyfill for browsers that don't support the sendAsBinary() method but support typed arrays.

|*|  :: XMLHttpRequest.prototype.sendAsBinary() Polyfill ::
|*|  https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest#sendAsBinary()

if (!XMLHttpRequest.prototype.sendAsBinary) {
  XMLHttpRequest.prototype.sendAsBinary = function (sData) {
    var nBytes = sData.length, ui8Data = new Uint8Array(nBytes);
    for (var nIdx = 0; nIdx < nBytes; nIdx++) {
      ui8Data[nIdx] = sData.charCodeAt(nIdx) & 0xff;
    /* send as ArrayBufferView...: */
    /* ...or as ArrayBuffer (legacy)...: this.send(ui8Data.buffer); */
Note: It's possible to build this polyfill putting two types of data as argument for send(): an ArrayBuffer (ui8Data.buffer – the commented code) or an ArrayBufferView (ui8Data, which is a typed array of 8-bit unsigned integers – uncommented code). However, on Google Chrome, when you try to send an ArrayBuffer, the following warning message will appear: ArrayBuffer is deprecated in XMLHttpRequest.send(). Use ArrayBufferView instead. Another possible approach to send binary data is the StringView Non native typed arrays superclass in conjunction with the send() method.

Browser compatibility

BCD tables only load in the browser