var request = false;

if(window.XMLHttpRequest){
  request = new XMLHttpRequest();
}else if(window.ActiveXObject){
  request = new ActiveXObject("Microsoft.XMLHTTP");
}

function getData(source){
  if(request){
    var data = document.getElementById("body");
    request.open("GET",source);
    request.onreadystatechange = function(){
      if(request.readyState==4){
        data.innerHTML = request.responseText;
      }
    }
    request.send(null);
  }
}