title: Javascript cross-domain web request fails with Status=0?
body: <p>EDIT: It's been pointed out below that this doesn't work because craigslist doesn't set an Allow-Cross-Domain header. OK, I'll buy that. Is there any other way to use javascript in firefox to download a page cross-domain then?</p>
  
  <hr>
  
  <p>Yes, I know the following code does not work in IE. I know IE expects me to use XDomainRequest() instead. I don't care about that. This is firefox only.</p>
  
  <p>I'm trying to do a cross-domain web request in firefox javascript. I keep getting a status of 0. Does anyone know why?</p>
  
  <pre><code>var url = "http://newyork.craigslist.org";
  var xdr = new XMLHttpRequest(); //Yes, I know IE expects XDomainRequest. Don't care
  xdr.onreadystatechange = function() { 
    if (xdr.readyState == 4) {
        alert(xdr.status); //Always returns 0! And xdr.responseText is blank too
    }
  }
  xdr.open("get", url, true);
  xdr.send(null);
  </code></pre>
  
  <p>Shouldn't that work? </p>