<!DOCTYPE html>
<title>drag &amp; drop - prompting before exposing files</title>
<style>
  body > div {
    height: 200px;
    width: 200px;
    background-color: orange;
  }
</style>

<script>
var filename = 'fail.png', filesize = '759', filetype = 'image/png';
var fails = [], finished = false;
window.onload = function() {
  var orange = document.getElementsByTagName('div')[0];
  orange.ondragover = orange.ondragenter = function(e) {
    e.preventDefault();
    e.dataTransfer.dropEffect = 'copy';
  };
  orange.ondrop = function(e) {
    e.preventDefault();
    if( !e.dataTransfer.files ) {
      fails[fails.length] = 'No dataTransfer.files for '+e.type;
    }
    if( !window.FileList ) {
      fails[fails.length] = 'No FileList interface object';
      finish();
      return;
    }
    if( !( e.dataTransfer.files instanceof FileList ) ) {
      fails[fails.length] = 'dataTransfer.files is not a FileList';
    }
    if( e.dataTransfer.files.length != 1 ) {
      fails[fails.length] = 'dataTransfer.files.length is '+e.dataTransfer.files.length+' instead of 1 for '+e.type;
    }
    if( !e.dataTransfer.files[0] ) {
      fails[fails.length] = 'no dataTransfer.files[0] for drop';
      finish();
      return;
    }
    if( e.dataTransfer.files[0].size != filesize ) {
      fails[fails.length] = 'dataTransfer.files[0].size '+e.dataTransfer.files[0].size+' instead of '+filesize;
    }
    /*
    if( !e.dataTransfer.files[0].lastModified ) {
      fails[fails.length] = 'no dataTransfer.files[0].lastModified';
    }
    */
    if( e.dataTransfer.files[0].name != filename ) {
      fails[fails.length] = 'dataTransfer.files[0].name '+e.dataTransfer.files[0].name+' instead of '+filename;
    }
    if( e.dataTransfer.files[0].type != filetype ) {
      fails[fails.length] = 'dataTransfer.files[0].type '+e.dataTransfer.files[0].type+' instead of '+filetype;
    }
    if( !window.FileReader ) {
      fails[fails.length] = 'No FileReader constructor';
      finish();
      return;
    }
    var reader = new FileReader();
    reader.onload = function () {
      if( !reader.result ) {
        fails[fails.length] = 'No file data after load';
      }
      if( reader.result.length != filesize ) {
        fails[fails.length] = 'File data length '+reader.result.length+' instead of '+filesize;
      }
      finish();
    };
    reader.readAsBinaryString(e.dataTransfer.files[0]);
    setTimeout(function () {
      if( !reader.result ) {
        fails[fails.length] = 'No file data after timeout';
      }
      finish();
    },1000);
  };

};
function finish() {
  if( finished ) { return; }
  finished = true;
  document.getElementsByTagName('p')[0].innerHTML = fails.length ? ( 'FAIL: ' + fails.join('<br>') ) : 'PASS';
}
</script>

<div></div>

<p>Save <a href="../resources/fail.png">this image</a> to your desktop. Use your pointing device to drag the saved file from your desktop onto the orange box, and release it. <strong>A confirmation dialog must appear, allowing you to choose to cancel the upload</strong>. Accept it. Fail if nothing happens, or if the browser simply displays the image, or if &quot;PASS&quot; appears as the page text <strong>before</strong> you have accepted the upload.</p>
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