title: php message Warning: Missing boundary in multipart/form-data POST data in Unknown on line 0
body: <p>This is my javascript</p>
  
  <pre><code>function ajax_post(){
              // Create our XMLHttpRequest object
              var hr = new XMLHttpRequest();
              // Create some variables we need to send to our PHP file
              var url = "LiveUpdate.php";
              var sb = document.getElementById("LiveUpdate").value;
              var FirstName = document.getElementById("FirstName").value;
              var images = document.getElementById("images").value;
  
              var vars = "update="+sb+"&amp;FirstName="+FirstName+"&amp;images="+images;
              hr.open("POST", url, true);
              // Set content type header information for sending url encoded variables in the request
              hr.setRequestHeader("Content-type", "multipart/form-data");
              // Access the onreadystatechange event for the XMLHttpRequest object
              hr.onreadystatechange = function() {
                  if(hr.readyState == 4 &amp;&amp; hr.status == 200) {
                      var return_data = hr.responseText;
                      document.getElementById("message").innerHTML = return_data;
                  }
              }
              // Send the data to PHP now... and wait for response to update the status div
              var formData = new FormData(document.querySelector("form"));
              hr.send(formData); // Actually execute the request // Actually execute the request
              document.getElementById("message").innerHTML = "processing...";
          }
              //show image before uploading
                  var loadFile = function(event) {
                  var output = document.getElementById('output');
                  output.src = URL.createObjectURL(event.target.files[0]);
                  };//end image
  </code></pre>
  
  <p>and this is the form. javascript and the form is in the same file. the file name is sample.php</p>
  
  <pre><code>&lt;form action="popup.php" method="post" id="myForm" name="myForm" enctype="multipart/form-data"&gt;
      &lt;div id="message"&gt;&lt;/div&gt;
      &lt;img src="" id="output" /&gt;
      &lt;input type="file" class="filestyle" data-buttonBefore="true" accept=".png, .jpg, .jpeg" onchange="loadFile(event)" name="images" id="images"&gt;
      &lt;input class="form-control" type="text" placeholder="First Name" name="FirstName" id="FirstName" value=""&gt;
      &lt;a href="#" class="btn btn-success" role="button" name="update" id="LiveUpdate"  onclick="javascript:ajax_post();"&gt;Update&lt;/a&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>the idea in this code is. i want to insert the basic information like FirstName and Image into the database live without refreshing the page. the reason why i choose  tag to submit the ajax. so the page url Account.php?Edit=1 will not change to Account.php because if it change to account.php the popup editing mode will be close. the problem in this code is. i don't know how to fix the error <code>Warning: Missing boundary in multipart/form-data POST data in Unknown on line 0</code> can anyone help me how to fix this. thank you!</p>