title: Uncaught TypeError: Failed to execute 'observe' on 'MutationObserver': parameter 1 is not of type 'Node'
body: <p>so my code below works stand alone in a jsfiddle. but for some odd reason.. I get this error consistently after pushing it to a live server :/ and I can't figure out why...</p>
  
  <p><strong>error</strong>:</p>
  
  <pre><code>mycodewitherror.js:23 Uncaught TypeError: Failed to execute 'observe' on 'MutationObserver': parameter 1 is not of type 'Node'.
  </code></pre>
  
  <p><strong>js:</strong></p>
  
  <hr>
  
  <pre><code>$(document).ready(function() {
  // The below collects user login name, new login date and time, and previous use URL
  var element = document.querySelector('.pet-name'); 
  // create an observer instance
  var observer = new MutationObserver(function(mutations) {
        var username = $('.pet-name').text();
        var referrer = document.referrer;
        var date = new Date();
        var month = date.getUTCMonth() + 1;
        var day = date.getUTCDate();
        var year = date.getUTCFullYear();
        var time = date.toLocaleTimeString();
        var formattedDate = month + '/' + day + '/' + year;
      console.log("Pet Name Time"); 
        console.log(referrer); 
        console.log(petname); 
        console.log(time); 
        console.log(formattedDate);   
  });
  
  // configuration of the observer:
  
  var config = { attributes: true, childList: true, characterData: true };
  
  // pass in the target node, as well as the observer options
  observer.observe(element, config);
  </code></pre>