Examples: Asynchronous Send

Front End
Back End

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Chapter 3 : XMLHttpRequest - Asynchronous Send</title>
<link rel="stylesheet" href="https://ajaxref.com/ch3/global.css" type="text/css" media="screen" />

<script type="text/javascript">

 
function createXHR()
{
   try { return new XMLHttpRequest(); } catch(e) {}
   try { return new ActiveXObject("Msxml2.XMLHTTP.6.0"); } catch (e) {}
   try { return new ActiveXObject("Msxml2.XMLHTTP.3.0"); } catch (e) {}
   try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) {}
   try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) {}
 
   return null;
}
 
function sendRequest()
{
    var xhr = createXHR();
    if (xhr)
    {
     xhr.open("GET", "https://ajaxref.com/ch3/helloworld.php", true);
     xhr.onreadystatechange = function(){handleResponse(xhr);};
     xhr.send(null);
    }
}
 
function handleResponse(xhr)
{
  if (xhr.readyState == 4  && xhr.status == 200)
    {
     var responseOutput = document.getElementById("responseOutput");
     responseOutput.innerHTML = "<h3>reponseText</h3>" + xhr.responseText;
     responseOutput.style.display = "";
    }
}
 
window.onload = function () 
{ 
 document.requestForm.requestButton.onclick = function () { sendRequest(); };
};

</script>

 
</head>
<body>
 
<form action="#" name="requestForm">
  <input type="button" name="requestButton" value="Send an Asynchronous Request" />
</form>
<br />
<div id="responseOutput" class="results" style="display:none;">&nbsp;</div>
 
</body>
</html>