Untitled

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" >
<meta http-equiv="expires" content="0">
<title>GetAllResponseHeaders</title>

</head>
<body>

<input type=button value="getAllResponseHeaders"
 onclick="getAllRespBTN()">
<div id="showPanel"></div>

<script>
var xhr = null;

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

  return xhr;
}

function stateChanged(){
  //server端處理完畢了没
  if (xhr.readyState == XMLHttpRequest.DONE ){
    if (xhr.status == 200){
        document.getElementById("showPanel").innerHTML = xhr.getAllResponseHeaders();
    }else{
        alert(xhr.status);
    }
  }
  //request做成功了嗎
}

function getAllRespBTN(){
  xhr = createXHR();
  if( xhr == null ){
    alert("Does not support Ajax...");
    return;
  }

  //設定好回呼函式
  xhr.onreadystatechange = stateChanged;

  //建立好Get連接
  var url = "GetAllResponseHeaders.jsp";
  xhr.open("Get",url, true);
  //送出請求
  xhr.send(null);

}
</script>
</body>
</html>