Check if cross domain url gives 404 with javascript

Question

I am trying this code but it gives me a DOM Exception. What I want it to get a true/false "answer" from the function using plain Javascript.

var url = 'http://www.google.com/';
function UrlExists(url)
{
  var http = new XMLHttpRequest();
  http.open('HEAD', url, false);
  http.send();
  return http.status!=404;
}
UrlExists(url);

FIDDLE

I got this code from this SO answer, but as said I cannot get it working...

Answer 1

Cross domain does not give any status code. status code is part of the content which is received from server when server responds with yes or no. In case of cross domain server never respond to request.

the second mistake in the code is you cannot capture the status code directly without any waiting time or success event. return statement in function doesn't wait until server response to ajax request, so you cannot depend on it.

Answer 2

Doesn't detect 404 errors, but can check if the page exists or not with a setTimeout() hack.

// Based on https://stackoverflow.com/a/18552771
// @author Irvin Dominin <https://stackoverflow.com/u/975520>
function UrlExists(url)
{
  var iframe = document.createElement('iframe');
  var iframeError; // Store the iframe timeout
  
  iframe.onload = function () {
    console.log("Success on " + url);
    clearTimeout(iframeError);
  }
  
  iframeError = setTimeout(function () {
    console.log("Error on " + url)
  }, 3000);
  
  iframe.src = url;
  document.getElementsByTagName("body")[0].appendChild(iframe);
}

UrlExists('http://www.google.com/');
UrlExists('http://www.goo000gle.com');