<script type="text/javascript">
var XMLHttpRequestObject = null;

try{
    XMLHttpRequestObject = new XMLHttpRequest();
}
catch(e){
  try{
    XMLHttpRequestObject =  new ActiveXObject("Microsoft.XMLHTTP");
  }
  catch(e){
  }
}

function processRequest()
{
  if (XMLHttpRequestObject.readyState == 4 &&
      XMLHttpRequestObject.status == 200){
    tekst = XMLHttpRequestObject.responseText;
    alert(tekst);
  }
}

function startRequest()
{
  if(XMLHttpRequestObject){
    XMLHttpRequestObject.open("GET", "http://localhost/dane.txt");
    XMLHttpRequestObject.onreadystatechange = processRequest;
    XMLHttpRequestObject.send(null);
  }
}
</script>