Question

I’m trying to check whether an URL returns 404, 403 etc when including a Javascript file. It works ok, but I still get an error in “Chrome developer tools”.

This is my code:

(function() { 
try
  {
            var ml = document.createElement('script'); 
        ml.type = 'text/javascript';    
        ml.async = true; 
        ml.id = 'monoloop_invoke'; 
        ml.onerror = function(){alert('File does not exist');};
        ml.src = 'http://somedomain.com/somefile.js';
            var s = document.getElementsByTagName('script')[0];
            s.parentNode.insertBefore(ml, s);

  }
catch(err)
  {
    alert('Error: '+err);
  }
        })
    ();     

If the file does not exist it shows the error “File does not exist” from the ml.onerror function. This is all good. But the problem is that I still get an error line in my console like:

GET http://somedomain.com/somefile.js 403 (Forbidden)

and the try/catch does not catch this error.

Anyone knows how to solve this? Or is there another way of testing if a URL exists before including it? I cannot use AJAX as I need to use this in a cross-domain fashion. I could use jQuery if necessary.

EDIT: It does not show an error in IE, so i guess this maybe just relates to the way chrome reports issues. Does anyone see a more elegant solution for checking if a file exisists without genreting anything in the console.

Answer 1

jQuery.getScript( url, [ success(data, textStatus) ] ) 

Description: Load a JavaScript file from the server using a GET HTTP request, then execute it.

url
A string containing the URL to which the request is sent.

success(data, textStatus)
A callback function that is executed if the request succeeds.

To catch the errors use the ajaxError event:

http://api.jquery.com/ajaxError/