simple AJAX

this is the AJAX implementation i use:

function jfetch(url,t,o) {
  var req = jfetch.xhr();
  req.open("GET",url,true);
  req.onreadystatechange = function() {
    if(req.readyState == 4){
      var rsp = req.responseText;
      if(t.constructor == Function) return t.apply(o,[rsp]);
      t = document.getElementById(t);
      t[t.value ==undefined ? 'innerHTML': 'value'] = rsp;
      req = null;
    }
  };
  req.send(null);
}
jfetch.xhr =
    (window.ActiveXObject)
   ? function(){ return new ActiveXObject("Microsoft.XMLHTTP"); }
   : function(){ return new XMLHttpRequest()};
it's short, it only checks for the transport (ActiveX or XHR) once, and it takes either an element id or a call back function. and, i can understand it.

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