title: e.nodeName is undefined jQuery (not working on Firefox only)
body: <p>I'm doing a basic form with an AJAX response but it didn't work (only) in FireFox; throwing this error in console: </p>
  
  <pre><code>TypeError: e.nodeName is undefined.
  </code></pre>
  
  <p>Here is my form (index.php) :</p>
  
  <pre><code>&lt;div id="frmContact"&gt;
  &lt;div id="mail-status"&gt;&lt;/div&gt;
  &lt;div&gt;
      &lt;label style="padding-top:20px;"&gt;Name&lt;/label&gt;
      &lt;span id="userName-info" class="info"&gt;&lt;/span&gt;&lt;br/&gt;
      &lt;input type="text" name="userName" id="userName" class="demoInputBox"&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;label&gt;Email&lt;/label&gt;
      &lt;span id="userEmail-info" class="info"&gt;&lt;/span&gt;&lt;br/&gt;
      &lt;input type="text" name="userEmail" id="userEmail" class="demoInputBox"&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;label&gt;Subject&lt;/label&gt; 
      &lt;span id="subject-info" class="info"&gt;&lt;/span&gt;&lt;br/&gt;
      &lt;input type="text" name="subject" id="subject" class="demoInputBox"&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;label&gt;Content&lt;/label&gt; 
      &lt;span id="content-info" class="info"&gt;&lt;/span&gt;&lt;br/&gt;
      &lt;textarea name="content" id="content" class="demoInputBox" cols="60" rows="6"&gt;&lt;/textarea&gt;
  &lt;/div&gt;
  &lt;div&gt;
  &lt;button name="submit" class="btnAction" onClick="sendContact();"&gt;Send&lt;/button&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p></p>
  
  <p>My javascript (end of index.php file) :</p>
  
  <pre><code>    &lt;script&gt;
  function sendContact() {
      var valid;  
      valid = validateContact();
      if(valid) {
          jQuery.ajax({
          url: "contact_mail.php",
          data:'userName='+$("#userName").val()+'&amp;userEmail='+$("#userEmail").val()+'&amp;subject='+$("#subject").val()+'&amp;content='+$(content).val(),
          type: "POST",
          success:function(data){
          },
          error:function (){}
          });
      }
  }
  
  function validateContact() {
      var valid = true;   
      $(".demoInputBox").css('background-color','');
      $(".info").html('');
  
      if(!$("#userName").val()) {
          $("#userName-info").html("(required)");
          $("#userName").css('background-color','#FFFFDF');
          valid = false;
      }
      if(!$("#userEmail").val()) {
          $("#userEmail-info").html("(required)");
          $("#userEmail").css('background-color','#FFFFDF');
          valid = false;
      }
      if(!$("#userEmail").val().match(/^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/)) {
          $("#userEmail-info").html("(invalid)");
          $("#userEmail").css('background-color','#FFFFDF');
          valid = false;
      }
      if(!$("#subject").val()) {
          $("#subject-info").html("(required)");
          $("#subject").css('background-color','#FFFFDF');
          valid = false;
      }
      if(!$("#content").val()) {
          $("#content-info").html("(required)");
          $("#content").css('background-color','#FFFFDF');
          valid = false;
      }
  
      return valid;
  }
  </code></pre>
  
  <p></p>
  
  <p>And contact_mail.php is the mail php function.</p>
  
  <p>Thanks for help people.</p>