Detect Tor Browser users and redirect them to the .onion version of my site.

tor-redirect.js

var myoniondomain = 'chrisdm326o2d7iq.onion';
var thecurrentdomain = window.location.hostname;
if (myoniondomain != thecurrentdomain) {
  function isTorBrowser() {
    var img = document.createElement('img');
    img.src = 'data:image/gif;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==';
    var canvas = document.createElement('canvas');
    canvas.width = 1;
    canvas.height = 1;
    var ctx = canvas.getContext('2d');
    var imagedata = ctx.getImageData(0, 0, canvas.width, canvas.height);
    return imagedata.data[0] == 255 && imagedata.data[1] == 255 && imagedata.data[2] == 255 && imagedata.data[3] == 255;
  };
  if (isTorBrowser()) {
    if (myoniondomain != thecurrentdomain) {
      var spinner = '<style>.loader{border:8px solid #ececec;border-radius:50%;border-top:8px solid #607d8b;width:60px;height:60px;-webkit-animation:spin 2s linear infinite;animation:spin 1s linear infinite;position: absolute; left: 50%; top: calc(50vh - 46px); margin: -30px 0 0 -30px;}@-webkit-keyframes spin{0%{-webkit-transform:rotate(0)}100%{-webkit-transform:rotate(360deg)}}@keyframes spin{0%{transform:rotate(0)}100%{transform:rotate(360deg)}}</style><div class="loader-container"><div class="loader"></div></div>';
      document.getElementsByTagName('html') [0].innerHTML = spinner;
      window.location = window.location.href.replace('https://chrisdavidmiles.com', 'http://chrisdm326o2d7iq.onion');
    }
  }
}

EDIT:

Don't use this code. I wrote it, and used it for a time, but this no longer works in most browsers that work with the tor network. Instead, use the Onion-Location HTTP response header. Websites can include this response header and have it include a link to the Onion site.

Anyone stumbling across this today should instead use the Onion-Location HTTP response header to redirect traffic to their Onion site.

Yes. I'll update my comment here and my old tor-redirect.js repo with information about Onion-Location header.