Is in China

README.md

Detecting if current browser is in China

Use the script below:

isInChina(function(inChina) {
  console.log('In china: ' + inChina);
})

If your page has a Content-Security-Policy header, add facebook url to it.

detect.js

function isInChina(cb) {
  var url = '//graph.facebook.com/feed?callback=h';
  var xhr = new XMLHttpRequest();
  var called = false;
  xhr.open('GET', url);
  xhr.onreadystatechange = function() {
    if (xhr.readyState === 4 && xhr.status === 200) {
      called = true;
      cb(false);
    }
  };
  xhr.send();
  // timeout 1s, this facebook API is very fast.
  setTimeout(function() {
    if (!called) {
      xhr.abort();
      cb(true);
    }
  }, 1000);
};