function load(obj,src) {
  var req = new XMLHttpRequest();
  if (req) {
    req.onreadystatechange = function() {
      if (req.readyState == 4 && req.status == 200) {
        remove(obj);
        var demo = document.getElementById(obj);
        demo.innerHTML = req.responseText;
      }
    };
    req.open('GET', src);
    req.send(null);
  }
}
function remove(obj) {
  var demo = document.getElementById(obj);
  while (demo.hasChildNodes()) {
    demo.removeChild(demo.firstChild);
  }
}