JavaScript readAsBinaryString Function on E11

FileReader.readAsBinaryString is a non-standard function and has been deprecated.

FileReader.readAsArrayBuffer should be used instead.

MDN


This is my solution.

var reader = new FileReader();
reader.readAsBinaryString(fileData);
reader.onload = function(e) {
  if (reader.result) reader.content = reader.result;
  var base64Data = btoa(reader.content);
  //...
}
//extend FileReader
if (!FileReader.prototype.readAsBinaryString) {
    FileReader.prototype.readAsBinaryString = function (fileData) {
       var binary = "";
       var pt = this;
       var reader = new FileReader();      
       reader.onload = function (e) {
           var bytes = new Uint8Array(reader.result);
           var length = bytes.byteLength;
           for (var i = 0; i < length; i++) {
               binary += String.fromCharCode(bytes[i]);
           }
        //pt.result  - readonly so assign binary
        pt.content = binary;
        $(pt).trigger('onload');
    }
    reader.readAsArrayBuffer(fileData);
    }
}

I combine @Jack answer with my comment to show a complete working example.

In the <head> section I added this script to add FileReader.readAsBinaryString function in IE11

if (FileReader.prototype.readAsBinaryString === undefined) {
    FileReader.prototype.readAsBinaryString = function (fileData) {
        var binary = "";
        var pt = this;
        var reader = new FileReader();
        reader.onload = function (e) {
            var bytes = new Uint8Array(reader.result);
            var length = bytes.byteLength;
            for (var i = 0; i < length; i++) {
                binary += String.fromCharCode(bytes[i]);
            }
            //pt.result  - readonly so assign content to another property
            pt.content = binary;
            pt.onload(); // thanks to @Denis comment
        }
        reader.readAsArrayBuffer(fileData);
    }
}

Then I needed to slightly modify my original script code because target.result has no value when using this fallback function.

var reader = new FileReader();
reader.onload = function (e) {
    // ADDED CODE
    if (!e) {
        var data = reader.content;
    }
    else {
        var data = e.target.result;
    }

    // business code
};
reader.readAsBinaryString(myFile);

Tags:

Javascript

Html

Internet Explorer

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