User:Hippietrail/hippajax.js

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// abstract function to do xmlhttprequest
function ajax(url, on200, on404) {
  var req = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');
  req.open('GET', url, true);
  req.onreadystatechange = function() {
    if (req.readyState == 4) {
      if (req.status == 200) {
        // TODO handle xmlhttprequest cache bug in some msie versions
        if (req.responseText == '') {
          on404();
        } else {
          on200(req);
        }
      } else if (req.status == 404) {
        on404();
      } else {
        debugPrint('bad rsc status ' + req.status + '\n');
      }
    }
  };
  req.send(null);
}