Monthly Archives: June 2008

The most basic Ajax with Java

Ajax is revolusioner method in building web application, it’s used javascript XMLHttpRequest object to communicate with server without have to reloading the page.

I am new to Ajax, this is my “hello world” application to show how using Ajax with Java.

(ajaxHello.jsp)

<html>
<head>
    <title>Hello Ajax</title>
</head>
<body>
    <script type="text/javascript">
        function ajaxFunction()
        {
        var xmlHttp;

        try
          {
          // Firefox, Opera 8.0+, Safari
          xmlHttp=new XMLHttpRequest();
          }
        catch (e)
          {
          // Internet Explorer
          try
            {
            xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
            }
          catch (e)
            {
            try
              {
              xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
              }
            catch (e)
              {
              alert("Your browser does not support AJAX!");
              return false;
              }
            }
          }

          xmlHttp.onreadystatechange=function()
            {
                if(xmlHttp.readyState==4)
                {
                    //document.myForm.time.value=xmlHttp.responseText;
                    document.getElementById("timeInfo").innerHTML=xmlHttp.responseText;
                }
            }

            xmlHttp.open("GET","time.jsp",true);
            xmlHttp.send(null);
        }
    </script>
<form name="aForm">
Name: <input type="text" name="username" onkeyup="ajaxFunction();" /> <br/>
Hi, you are typing the text at
<span id="timeInfo" STYLE="font-family: sans-serif; color: red; font-size: 12pt"></span>
</form>
</body>
</html>

(time.jsp)

<%= new java.text.SimpleDateFormat("dd MMM yyyy, hh:mm:ss").format( new java.util.Date() ) %>

This is the source, rename it to AjaxWithJavaHello.war and plug into your web server.