function validate_form()
{
    var captcha = document.getElementById("lcaptcha");
    if (captcha.value == null || captcha.value == "") {
        alert("Type the letters from the image above");
        captcha.focus();
        return false;
    }
    if (validate_captcha(captcha.value) == 0) 
    {
        alert("Please enter the correct letters.");
        captcha.focus();
        return false;
    }
    document.captcha_form.action = "/process/" + "sendmail_vno.phtml";
    document.captcha_form.method = "p" + "ost";
    return true;
}

function validate_captcha(in_captcha)
{
   var response  =  new Ajax.Request(
            "/investor_relations/k.php",
           {
              parameters: {captcha: in_captcha
                          },
              method:'post',
              asynchronous: false
            }
    );
    return response.transport.responseText;
}