title: http://localhost/undefined 404 (Not Found)
body: <p>I was not clear in my problem description.  Let me try again.</p>
  
  <p>NB.  This is a problem common to my production, staging, and development sites (not just to my delevlopment site as the commenters seem to have thought).</p>
  
  <p>NB.  This problem occurs bowsing with Chrome and not with Firefox.</p>
  
  <p>The problem occurs at the site home page: <a href="http://www.example.com" rel="noreferrer">http://www.example.com</a> (or with "/index.php appended").  The page loads successfully, but the Console pannel of Chrome's Developer Tools shows a 404 error.  The message reads "GET <a href="http://www.example/undefined" rel="noreferrer">http://www.example/undefined</a> 404 (Not Found)".  It always shows the error as occuring at "(index):1" which is the DOCTYPE line.  Whatever is generating the problem, it is not that.</p>
  
  <p>The page is loading fine, I just get this odd message in the Developers Tools Console.  (I probably wasn't clear about that in the original problem description.)  Firfox's console shows no such error.</p>
  
  <p>I want to track down what is generating this error.  In particular, I would like to find where Chrome is getting the "undefined" url.  My guess (but only a guess) is that one of my many Javascript files is genrating a URL from an undefined variable.  Chrome's location of the problem, "(index):1", is wrong.  I would appreciate any ideas as to how to get a more useful error message out of Chrome: the name of the file where the URL was found would help.  If I can do this without having set breakpoints in all my Javascript files one by one, that would be particularly nice. :-)</p>
  
  <p>The original question with URL's removed (I'm limited in the number of links I'm allowed with a reputation &lt; 10) follows.  You may not want to read it as people have been confused by it.</p>
  
  <blockquote>
    <p>We have rather complex Drupal website.  When going to the homepage,
    the Chrome (Version 45.0.2454.85 m) Console shows me an error: "[URL
    removed] 404 (Not Found)  (index):1".  (I'm using the development site
    on my local computer because minification is turned off there.)<br>
    Okay, I think, I know what to do about that:  Go find the offending
    spot in whatever file, scratch my head a few times, get a brilliant
    idea, and fix the problem.  One little difficulty:  the problem is
    surely <strong>not</strong> occurring at index, line 1 (which I assume is what
    "(index):1" means).  The "undefined" in the error message suggests but
    does not prove that the offender is one of our about a dozen
    JavaScript files.  Presumably some variable somewhere is undefined. 
    So how do I get Chrome to cough up the location where the offense is
    occurring?  It is not giving me any undefined value JavaScript errors,
    just a 404 on [URL removed]/undefined .  Thanks in advance for any
    ideas.</p>
    
    <p>Edit:  I forgot to add that Firefox is showing no such error.</p>
  </blockquote>