read the HTTP header to check for 404 with jQuery without performing an ajax request

Question

Is there a way to read the HTTP header with jQuery without performing a .ajax request and reading xhr.status ?

Along similar lines to the popular Google Analytics addon ( gaAddons ) I wish to track 404s on my site. Unfortunately, I have inherited a legacy system and 404s do not have a unique URL.

Is it possible to read the HTTP header using jQuery?

Answer 1

I don't think this is possible - they are not exposed to JavaScript. An AJAX request is the obvious workaround - not sure why you're against this.

More info in this question: Accessing the web page's HTTP Headers in JavaScript

Answer 2

If you have access to the 404 error page, you could inject javascript into the 404 page that can send page details like, url, time etc to server through ajax [but it's point less if they are in server logs]. But then, this script can be exploited.

Answer 3

You might be able to do something like this in jQuery:

if ( $('meta[content="Not Found - The URL you requested could not be found."]').length>0 ) {
    /* do something about it */
}

This assumes that the delivery engine has put the following meta tag in the header of the page. Tumblr does this, for example. Your own system may put a different meta tag or you could design your system to deliver some such meta tag.

<meta name="description" content="Not Found - The URL you requested could not be found." />

Of course, all this is really doing is checking the meta header which offers a page summary. But you could take advantage of the mechanism in your own environment.

Answer 4

While doing site analytics i had to record errors separately.

Similar to @Octopus suggestion i added a meta tag to 404 and 500 pages.

<meta name="error" content="404">

On the client i then checked if this meta tag existed like so:

<script>
  meta = document.getElementsByTagName('meta');

  for (i=0; i< meta.length; i++) {

    if(meta[i].name == 'error'){
       alert('This page returned a ' + meta[i].content + ' error');   
    }

  }

</script>

Unfortunately i had to use vanilla JS to achieve this.