gistfile1.js

document
          .getElementById("dropzone")
          .addEventListener("drop", function(event) {

     // get dropped files
     var files = event.dataTransfer.files;
     
     // iterate over dropped files
     for (var i = 0; i < files.length; i++) {
           console.log(files[i]);
           
           var xhr = new XMLHttpRequest();
           var upload = xhr.upload;
           upload.fileIndex = i;
           upload.fileObj = files[i];
           upload.downloadStartTime = new Date().getTime();
           upload.currentStart = upload.downloadStartTime;
           upload.currentProgress = 0;
           upload.startData = 0;

           xhr.setRequestHeader("Cache-Control", "no-cache");
           xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
           xhr.setRequestHeader("X-File-Name", files[i].fileName);
           xhr.setRequestHeader("X-File-Size", files[i].fileSize);
           xhr.setRequestHeader("Content-Type", "application/octet-stream");
     }

     event.preventDefault();
}, true);