<%@ Page Language=”C#” AutoEventWireup=”true” CodeFile=”AjaxCaptcha.aspx.cs” Inherits=”AjaxCaptcha” %>
<!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>
<title>Ajax Captcha</title>
<script language=”javaScript” type=”text/javascript”>
var url = ‘Services/AjaxServiceRequestPages/CheckImageCaptcha.aspx?code=’;
var captchaOK = 2; // 2 – not yet checked, 1 – correct, 0 – failed
function getHTTPObject()
{
try
{
req = new XMLHttpRequest();
}
catch (err1)
{
try
{
req = new ActiveXObject(“Msxml12.XMLHTTP”);
}
catch (err2)
{
try
{
req = new ActiveXObject(“Microsoft.XMLHTTP”);
}
catch (err3)
{
req = false;
}
}
}
return req;
}
var http = getHTTPObject(); // We create the HTTP Object
function handleHttpResponse()
{
if (http.readyState == 4)
{
captchaOK = http.responseText.charAt(0);
if(captchaOK != 1)
{
alert(‘The entered code was not correct. Please try again’);
document.forms[0].code.value=”;
document.forms[0].code.focus();
return false;
}
document.forms[0].submit();
}
}
function checkcode(thecode)
{
http.open(“GET”, url + escape(thecode), true);
http.onreadystatechange = handleHttpResponse;
http.send(null);
}
function checkform()
{
// First the normal form validation
if(document.forms[0].req.value==”)
{
alert(‘Please complete the “required” field’);
document.forms[0].req.focus();
return false;
}
if(document.forms[0].code.value==”)
{
alert(‘Please enter the string from the displayed image’);
document.forms[0].code.value=”;
document.forms[0].code.focus();
return false;
}
// Now the Ajax CAPTCHA validation
checkcode(document.forms[0].code.value);
return false;
}
</script>
</head>
<body>
<form name=”myform” runat=”server”>
<table>
<tr>
<td>
Required field:
</td>
<td>
<input type=”text” name=”req” value=”" />
</td>
</tr>
<tr>
<td>
Optional field:
</td>
<td>
<input type=”text” name=”opt” value=”" />
</td>
</tr>
<tr>
<td>
Captcha image:
</td>
<td>
<img alt=”Security Image” src=”Services/AjaxServiceRequestPages/SecurityCodeImage.aspx”/>
</td>
</tr>
<tr>
<td>
String:
</td>
<td>
<input type=”text” name=”code” value=”" />
</td>
</tr>
<tr>
<td>
</td>
<td>
<input type=”submit” value=”Submit Form” onclick=”return checkform()” />
</td>
</tr>
</table>
</form>
</body>
</html>
