項目の削除を行いたいのですが、
どのように実装したら良いか分かりません。
具体的には、アップロードした各ファイル名の右に削除ボタンを設け、ボタンを押下するとその項目が削除されるようにしたいです。

/*
filedrag.js - HTML5 File Drag & Drop demonstration
Featured on SitePoint.com
Developed by Craig Buckler (@craigbuckler) of OptimalWorks.net
*/
(function() {

 // getElementById
 function $id(id) {
  return document.getElementById(id);
 }


 // output information
 function Output(msg) {
  var m = $id("messages");
  m.innerHTML = msg + m.innerHTML;
 }


 // file drag hover
 function FileDragHover(e) {
  e.stopPropagation();
  e.preventDefault();
  e.target.className = (e.type == "dragover" ? "hover" : "");
 }


 // file selection
 function FileSelectHandler(e) {

  // cancel event and hover styling
  FileDragHover(e);

  // fetch FileList object
  var files = e.target.files || e.dataTransfer.files;

  // process all File objects
  for (var i = 0, f; f = files[i]; i++) {
   ParseFile(f);
  }

 }


 // output file information
 function ParseFile(file) {

  Output(
   "<p>File information: <strong>" + file.name +
   "</strong> type: <strong>" + file.type +
   "</strong> size: <strong>" + file.size +
   "</strong> bytes</p>"
  );

 }


 // initialize
 function Init() {

  var fileselect = $id("fileselect"),
   filedrag = $id("filedrag"),
   submitbutton = $id("submitbutton");

  // file select
  fileselect.addEventListener("change", FileSelectHandler, false);

  // is XHR2 available?
  var xhr = new XMLHttpRequest();
  if (xhr.upload) {

   // file drop
   filedrag.addEventListener("dragover", FileDragHover, false);
   filedrag.addEventListener("dragleave", FileDragHover, false);
   filedrag.addEventListener("drop", FileSelectHandler, false);
   filedrag.style.display = "block";

   // remove submit button
   submitbutton.style.display = "none";
  }

 }

 // call initialization file
 if (window.File && window.FileList && window.FileReader) {
  Init();
 }


})();
/*
Styles for HTML5 File Drag & Drop demonstration
Featured on SitePoint.com
Developed by Craig Buckler (@craigbuckler) of OptimalWorks.net
*/
body
{
 font-family: "Segoe UI", Tahoma, Helvetica, freesans, sans-serif;
 font-size: 90%;
 margin: 10px;
 color: #333;
 background-color: #fff;
}

#filedrag
{
 display: none;
 font-weight: bold;
 text-align: center;
 padding: 1em 0;
 margin: 1em 0;
 color: #555;
 border: 2px dashed #555;
 border-radius: 7px;
 cursor: default;
}

#filedrag.hover
{
 color: #f00;
 border-color: #f00;
 border-style: solid;
 box-shadow: inset 0 3px 4px #888;
}

img
{
 max-width: 100%;
}

pre
{
 width: 95%;
 height: 8em;
 font-family: monospace;
 font-size: 0.9em;
 padding: 1px 2px;
 margin: 0 0 1em auto;
 border: 1px inset #666;
 background-color: #eee;
 overflow: auto;
}

#messages
{
 padding: 0 10px;
 margin: 1em 0;
 border: 1px solid #999;
}

#progress p
{
 display: block;
 width: 240px;
 padding: 2px 5px;
 margin: 2px 0;
 border: 1px inset #446;
 border-radius: 5px;
 background: #eee url("progress.png") 100% 0 repeat-y;
}

#progress p.success
{
 background: #0c0 none 0 0 no-repeat;
}

#progress p.failed
{
 background: #c00 none 0 0 no-repeat;
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>HTML5 File Drag &amp; Drop API</title>
<link rel="stylesheet" type="text/css" media="all" href="styles.css" />
</head>
<body>
<form id="upload" action="index.html" method="POST" enctype="multipart/form-data">

<fieldset>
<legend>HTML File Upload</legend>

<input type="hidden" id="MAX_FILE_SIZE" name="MAX_FILE_SIZE" value="300000" />

<div>
 <label for="fileselect">Files to upload:</label>
 <input type="file" id="fileselect" name="fileselect[]" multiple="multiple" />
 <div id="filedrag">or drop files here</div>
</div>

<div id="submitbutton">
 <button type="submit">Upload Files</button>
</div>

</fieldset>

</form>

<div id="messages">
<p>Status Messages</p>
</div>


<script src="filedrag.js"></script>
</body>
</html>