title: XHR upload and the moment the upload begins
body: <p>I'm attempting to find a way when an upload is initiated with XHR so I can do something; I looked around and read that <code>.loadstart</code> was for when the request starts (which means what exactly?) and this is what I had:</p>
  
  <pre><code>function processUpload(file, postName, onLoadCallback, onErrorCallBack, onProgressCallBack, startCallBack)
  {    
      var xhr = new XMLHttpRequest();
      var fD = new FormData();
  
      for(var i = 0; i &lt; file.length; i++)
      {
          xhr.open("POST", "PATHHERE");
  
          xhr.loadstart = startCallBack;
  
          xhr.onload =  onLoadCallback;
  
          xhr.onerror = onErrorCallBack;
  
          xhr.upload.onprogress = onProgressCallBack;
  
          fD.append(postName, file[i]);
          xhr.send(fD);
      }
  }
  </code></pre>
  
  <p>Also, I'm unsure if a for loop is the best way of going about doing multiple file uploads. I feel as though that could get heavy on the site. What is the better method of doing that?</p>