XMLHttpRequest only working for local host

Question

I am trying to check internet connection in js:

function doesConnectionExist() {
  var xhr = new XMLHttpRequest();
  var file = "https://www.google.com";
  var randomNum = Math.round(Math.random() * 10000);

  xhr.open('HEAD', file + "?rand=" + randomNum, true);
  xhr.send();

  xhr.addEventListener("readystatechange", processRequest, false);

  function processRequest(e) {

    if (xhr.readyState == 4) {
      if (xhr.status >= 200 && xhr.status < 304) {                   
        alert("connection ok");
      } else {
        alert("connection doesn't exist!");
      }
    }
  }
}

Its not working, showing:

connection doesn't exist!

if I pass "localhost/myApp" Instead of "www.google.com", it works fine, but if I pass my IP instead of "localhost", it's not working that time again.

Javascript by default blocks all cross site ajax requests. It will only work with ur localhost. — Harry Bomrah, Dec 22 '16 at 09:19
You can refer to this https://www.html5rocks.com/en/tutorials/cors/ — Kim Hoang, Dec 22 '16 at 09:23
possible duplicate of http://stackoverflow.com/questions/8679736/allowing-cross-domain-requests-in-safari-and-chrome-server-response-vs-command — Kiran Kumar, Dec 22 '16 at 09:23
how to resolve? get google to send CORS headers for you ... or use a service designed for such tests, one that supports CORS ... or do the test server side, since the page is loaded from localhost, do the test from the server running on localhost — Jaromanda X, Dec 22 '16 at 09:23
check this question: http://stackoverflow.com/questions/20043215/check-internet-connectivity-with-jquery — Webdeveloper_Jelle, Dec 22 '16 at 09:24

score 1 · Answer 1 · answered Dec 22 '16 at 09:40

You can use a proxy server with CORS enabled if your requirement is simple. You can even have a proxy server of your own setup with a similar service. If you are just checking uptime of a single server, then it is better to enable CORS in your server for this service.

function doesConnectionExist(url) {
  var xhr = new XMLHttpRequest();
  var file = "http://cors-anywhere.herokuapp.com/" + url;
  var randomNum = Math.round(Math.random() * 10000);

  xhr.open('HEAD', file + "?rand=" + randomNum, true);
  xhr.send();

  xhr.addEventListener("readystatechange", processRequest, false);

  function processRequest(e) {
    if (xhr.readyState == 4) {
      console.log(url, xhr.status);
      if (xhr.status >= 200 && xhr.status < 304) {

        console.log("connection ok");
      } else {
        console.log("connection doesn't exist!");
      }
    }
  }
}
doesConnectionExist("http://www.marotikkaya.in");
doesConnectionExist("http://www.google.com");

XMLHttpRequest only working for local host

1 Answers1