var xmlHttp = false;
try {
  xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
  try {
    xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
  } catch (e2) {
    xmlHttp = false;
  }
}
if (!xmlHttp && typeof XMLHttpRequest != 'undefined') {
  xmlHttp = new XMLHttpRequest();
}

function callServer() {
  var url = "news_top5.asp";
  xmlHttp.open("GET", url, true);
  xmlHttp.onreadystatechange = updatePage;
  xmlHttp.send(null); 
}
function updatePage() {
  if (xmlHttp.readyState < 4) {
    document.getElementById("UserName_explain").innerHTML=response;
  }
  if (xmlHttp.readyState == 4) {
    var response = xmlHttp.responseText;
    document.getElementById("UserName_explain").innerHTML=response;
  }
}