var url = './ajax/captcheck.php?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;
            if(captchaOK != 1) {
              alert('The entered code was not correct. Please try again');
              document.getElementById('verif_box').value='';
              document.getElementById('verif_box').focus();
              return false;
              }
              document.sampleform.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.getElementById('verif_box').value=='') {
          alert('Please enter the string from the displayed image');
          document.getElementById('verif_box').value='';
          document.getElementById('verif_box').focus();
          return false;
          }
          // Now the Ajax CAPTCHA validation
          checkcode(document.getElementById('verif_box').value);
          return false;
        }