title: How to pass hidden values with ajax upload form
body: <p>I'm busying with passing some values of hidden input with an ajax form. I've tried may ways but it looks like the values didn't go through.</p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;form id="upload_form" enctype="multipart/form-data" method="post"&gt;
      &lt;input type="hidden" name="sid" value="$rec_sStdi[std_sid]" /&gt;
      &lt;input type="hidden" name="stid" value="$rec_sStdi[stdi_sid]" /&gt;
      &lt;input type="text" name="title" class="form-control" size="50" maxlength="128" autocomplete="off" placeholder="ชื่อไฟล์ เช่น แบบประเมินครู เป็นต้น"/&gt;
      &lt;progress id="progressBar" value="0" max="100" style="width:100%;"&gt;&lt;/progress&gt;                          
      &lt;button class="btn btn-primary btn-xs pull-right" type="button" value="Upload File" onclick="uploadFile()"&gt;&lt;i class="glyphicon glyphicon-upload"&gt;&lt;/i&gt;&amp;nbsp;อัพโหลด&lt;/button&gt;
      &lt;input type="file" name="file1" id="file1" class="btn btn-danger btn-xs pull-right"&gt;
    &lt;b id="status"&gt;&lt;/b&gt;
    &lt;p id="loaded_n_total"&gt;&lt;/p&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p><strong>Javascript</strong></p>
  
  <pre><code>function _(el){
      return document.getElementById(el);
  }
  function uploadFile(){
      var file = _("file1").files[0];
      //alert(file.name+" | "+file.size+" | "+file.type);
      var formdata = new FormData();
      formdata.append("file1", file);
      var ajax = new XMLHttpRequest();
      ajax.upload.addEventListener("progress", progressHandler, false);
      ajax.addEventListener("load", completeHandler, false);
      ajax.addEventListener("error", errorHandler, false);
      ajax.addEventListener("abort", abortHandler, false);
      ajax.open("POST", "inc/eval_file_upload.php");
      ajax.send(formdata);
  }
  function progressHandler(event){
      _("loaded_n_total").innerHTML = "Uploaded "+event.loaded+" bytes of "+event.total;
      var percent = (event.loaded / event.total) * 100;
      _("progressBar").value = Math.round(percent);
      _("status").innerHTML = Math.round(percent)+"% uploaded... please wait";
  }
  function completeHandler(event){
      _("status").innerHTML = event.target.responseText;
      _("progressBar").value = 0;
  }
  function errorHandler(event){
      _("status").innerHTML = "Upload Failed";
  }
  function abortHandler(event){
      _("status").innerHTML = "Upload Aborted";
  }
  </code></pre>
  
  <p><strong>PHP (eval_file_upload.php)</strong></p>
  
  <pre><code>&lt;?
  $sid=$_POST['sid'];
  $stid=$_POST['stid'];
  $title=$_POST['title'];
  
  $fileName = $_FILES["file1"]["name"]; // The file name
  $fileTmpLoc = $_FILES["file1"]["tmp_name"]; // File in the PHP tmp folder
  $fileType = $_FILES["file1"]["type"]; // The type of file it is
  $fileSize = $_FILES["file1"]["size"]; // File size in bytes
  $fileErrorMsg = $_FILES["file1"]["error"]; // 0 for false... and 1 for true
  if (!$fileTmpLoc) { // if file not chosen
      echo "ERROR: Please browse for a file before clicking the upload button.";
      exit();
  }
  if(move_uploaded_file($fileTmpLoc, "../files/$fileName")){
  
      echo "\"$fileName\" upload is complete (sid:$sid , stid:$stid, title:$title)";  
  } else {
      echo "move_uploaded_file function failed";
  }
  ?&gt;
  </code></pre>
  
  <p>I tried to test the passing by echoing the hidden values. But nothing shows up. 
  ref : <a href="http://www.developphp.com/view.php?tid=1351" rel="nofollow">http://www.developphp.com/view.php?tid=1351</a></p>