AI-generated Key Takeaways
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reCAPTCHA v1.0 is deprecated; upgrade to v2.0 for continued support.
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This guide demonstrates how to integrate reCAPTCHA into classic ASP websites to prevent bot abuse.
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Provided ASP code snippets enable rendering the reCAPTCHA widget and validating user responses.
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Sample HTML illustrates how to display the reCAPTCHA challenge and handle success/failure scenarios within your ASP page.
Important: Version 1.0 of the reCAPTCHA API is no longer supported, please upgrade to Version 2.0. Learn more
The reCAPTCHA ASP guide provides a simple way to place a CAPTCHA on your ASP page, helping you stop bots from abusing it. The code below wraps the reCAPTCHA API.
After you've signed up for your API keys, you can add reCAPTCHA to your classic ASP site by pasting the code below at the top of your ASP page:
<%
recaptcha_challenge_field = Request("recaptcha_challenge_field")
recaptcha_response_field = Request("recaptcha_response_field")
recaptcha_public_key = "your_public_key" ' your public key
recaptcha_private_key = "your_private_key" ' your private key
' returns the HTML for the widget
function recaptcha_challenge_writer()
recaptcha_challenge_writer = _
"<script type=""text/javascript"">" & _
"var RecaptchaOptions = {" & _
" theme : 'red'," & _
" tabindex : 0" & _
"};" & _
"</script>" & _
"<script type=""text/javascript"" src=""http://www.google.com/recaptcha/api/challenge?k=" & recaptcha_public_key & """></script>" & _
"<noscript>" & _
"<iframe src=""http://www.google.com/recaptcha/api/noscript?k=" & recaptcha_public_key & """ frameborder=""1""></iframe><>" & _
"<textarea name=""recaptcha_challenge_field"" rows=""3"" cols=""40""></textarea>" & _
"<input type=""hidden"" name=""recaptcha_response_field""value=""manual_challenge"">" & _
"</noscript>"
end function
' returns "" if correct, otherwise it returns the error response
function recaptcha_confirm(rechallenge,reresponse)
Dim VarString
VarString = _
"privatekey=" & recaptcha_private_key & _
"&remoteip=" & Request.ServerVariables("REMOTE_ADDR") & _
"&challenge=" & rechallenge & _
"&response=" & reresponse
Dim objXmlHttp
Set objXmlHttp = Server.CreateObject("Msxml2.ServerXMLHTTP")
objXmlHttp.open "POST", "https://www.google.com/recaptcha/api/verify", False
objXmlHttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
objXmlHttp.send VarString
Dim ResponseString
ResponseString = split(objXmlHttp.responseText, vblf)
Set objXmlHttp = Nothing
if ResponseString(0) = "true" then
'They answered correctly
recaptcha_confirm = ""
else
'They answered incorrectly
recaptcha_confirm = ResponseString(1)
end if
end function
server_response = ""
newCaptcha = True
if (recaptcha_challenge_field <> "" or recaptcha_response_field <> "") then
server_response = recaptcha_confirm(recaptcha_challenge_field, recaptcha_response_field)
newCaptcha = False
end if
%>
What happens here is the variables server_response and newCaptcha are set whenever the
page is loaded, allowing you to determine the state of your page.
You can use the following HTML as a skeleton:
<html> <body> <% if server_response <> "" or newCaptcha then %> <% if newCaptcha = False then %> <!-- An error occurred --> Wrong! <% end if %> <!-- Generating the form --> <form action="recaptcha.asp" method="post"> <%=recaptcha_challenge_writer()%> </form> <% else %> <!-- The solution was correct --> Correct! <%end if%> </body> </html>