ASP Classic CAPTCHA Code Filtering VBScript Code Sample

documentation > asp classic captcha > samples

The ASP Classic Captcha code filtering sample project shows how to use the new CAPTCHA code filtering functionality added in BotDetect CAPTCHA v3.0.

First Time Here?

Check the BotDetect Developer Crash Course for key integration steps.

You can define rules about character sequences you want to avoid using in randomly generated CAPTCHA codes and simply pass them to the Captcha control.

The BotDetect/CaptchaConfig.asp file defines a simplified custom character set (using only 'A', 'B', 'C' and 'D'), which helps make the code filtering easier to track in action.

The LBD_Configured_BannedSequences setting in the same file shows how to create your own banned sequence definitions to suit your application needs. The following sequences will never appear in Captcha codes generated in the sample: D, AA, BB, CC, ABC, BCA, CAB.

Installed Location

By default, the Classic ASP basic Captcha sample project is installed at:
C:\Program Files\Lanapsoft\BotDetect 3 CAPTCHA Component\Asp\WebApp\CaptchaCodeFilteringSample

You can also run it from the BotDetect Start Menu:
Programs > Lanapsoft > BotDetect 3 CAPTCHA Component > ASP > Web Applications > Run

Download the BotDetect Classic ASP CAPTCHA Component and run this sample

Default.asp
BotDetect\CaptchaConfig.asp

Default.asp

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.
w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
  <title>BotDetect ASP CAPTCHA Code Filtering Sample</title>
  <link type="text/css" rel="Stylesheet" href="StyleSheet.css" />
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  <!-- #include file ="BotDetect.asp" -->
</head>
<body>
  <form method="post" action="" id="form1">

    <h1>BotDetect ASP CAPTCHA Code Filtering Sample</h1>
    
    <fieldset>
      <legend>ASP CAPTCHA validation</legend>
      <label for="CaptchaCode">Retype the characters from the picture:
      </label>
      
      <% ' Adding BotDetect CAPTCHA to the page 
        Dim SampleCaptcha : Set SampleCaptcha = (New Captcha)("SampleCaptcha")
        SampleCaptcha.UserInputID = "CaptchaCode"
        Response.Write SampleCaptcha.Html %>
      
      <div class="validationDiv">
        <input name="CaptchaCode" type="text" id="CaptchaCode" />
        <input type="submit" name="ValidateCaptchaButton" 
        value="Validate" id="ValidateCaptchaButton" />
        
        <% ' CAPTCHA user input validation (only if the form was 
        sumbitted)
          If Request.ServerVariables("REQUEST_METHOD") = "POST" Then
            Dim isHuman : isHuman = SampleCaptcha.Validate()
            If Not isHuman Then 
              ' CAPTCHA validation failed, show error message
              Response.Write "<span class=""incorrect"">Incorrect code
              </span>"
            Else 
              ' CAPTCHA validation passed, perform protected action
              Response.Write "<span class=""correct"">Correct code
              </span>"
            End If 
          End If
        %>
      </div>
    </fieldset>

  </form>
</body>
</html>

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BotDetect\CaptchaConfig.asp

<%

' Captcha code configuration
' ---------------------------------------------------------------------
LBD_Configuration_CodeLength = 5
LBD_Configuration_CodeStyle = 0
LBD_Configuration_CodeTimeout = 1200
LBD_Configuration_Locale = "en-US"
LBD_Configuration_CustomCharset = "A,B,C,D"
LBD_Configuration_BannedSequences = "d,aa,bb,cc,abc,bca,cab,"


' Captcha image configuration
' ---------------------------------------------------------------------
LBD_Configuration_ImageStyle = LBD_RandomFromRange(0, 59)
LBD_Configuration_ImageWidth = 250
LBD_Configuration_ImageHeight = 50
LBD_Configuration_ImageFormat = 0
LBD_Configuration_CustomDarkColor = ""
LBD_Configuration_CustomLightColor = ""
LBD_Configuration_HelpLinkEnabled = True
LBD_Configuration_HelpLinkUrl = "http://captcha.biz/captcha.html"
LBD_Configuration_ImageTooltip = "CAPTCHA"


' Captcha sound configuration
' ---------------------------------------------------------------------
LBD_Configuration_SoundEnabled = True
LBD_Configuration_SoundStyle = LBD_RandomFromRange(0, 9)
LBD_Configuration_SoundFormat = 0
LBD_Configuration_SoundTooltip = "Speak the CAPTCHA code"
LBD_Configuration_SoundIconUrl = "BotDetect/SoundIcon.gif"
LBD_Configuration_SoundPackageFolder = "C:\Program Files (x86)
\Lanapsoft\BotDetect 3 CAPTCHA 
Component\Asp\Redistribute\BotDetectSounds"
LBD_Configuration_WarnAboutMissingSoundPackages = True


' Captcha reload configuration
' ---------------------------------------------------------------------
LBD_Configuration_ReloadEnabled = True
LBD_Configuration_ReloadTooltip = "Reload the CAPTCHA code"
LBD_Configuration_ReloadIconUrl = "BotDetect/ReloadIcon.gif"
LBD_Configuration_AutoReloadExpiredCaptchas = True
LBD_Configuration_AutoReloadTimeout = 7200


' Captcha user input  configuration
' ---------------------------------------------------------------------
LBD_Configuration_AutoFocusInput = True
LBD_Configuration_AutoClearInput = True
LBD_Configuration_AutoLowercaseInput = True


' Captcha persistence configuration
' ---------------------------------------------------------------------
Dim LBD_Persistence : Set LBD_Persistence = Session
LBD_Configuration_UseApplicationFallback = True

%>