BotDetect PHP CAPTCHA Web API Reference

Numeric representation of the Captcha CodeStyle, i.e. the algorithm used to generate Captcha codes from default pre-defined locale character sets; the default value is 0.

Numeric representation of the Captcha ImageStyle, i.e. the algorithm used to render Captcha codes in images; the default image style is 0.

Numeric representation of the ImageFormat in which the Captcha image will be generated; the default format is 0.

Captcha sound style - can be a fixed or a randomized value selected from the 10 BotDetect sound generation algorithms.

Captcha sound output format (WavPcm16bit8KhzMono or WavPcm8bit8KhzMono).

BotDetect audio Captcha sound regeneration mode determining how will multiple consecutive requests for audio Captcha with the same Captcha code be handled by BotDetect; the default mode is Limited.

Starting tabindex for the Captcha control Html output.

The keyboard-selectable Captcha markup elements are: the Captcha reload icon, the Captcha sound icon, and (only in the Free version of BotDetect) the BotDetect website link.

• If $p_UserInput (the user input of the Captcha code) is specified, the passed value is used for validation; if it's left null, the code will try to automatically find and read the POST parameter named as specified in the UserInputId field.
• If $p_InstanceId (the InstanceId of the Captcha code that is being validated) is specified, the passed value is used for validation; if it's left null, the code will try to automatically read it from the hidden field included in Captcha markup.

In most cases, you will call this function without any parameters ($Captcha->Validate()). The optional parameters can be used for Captcha integration in advanced scenarios where the default functionality won't be enough

The separation of Ajax validation from regular Captcha validation is necessary because there is a fundamental difference in their behavior.

Captcha validation always deletes the stored Captcha code on validation (allowing only one Captcha validation attempt of each Captcha code for security purposes, regardless if validation succeeds or fails).

Since successful Ajax Captcha validation will often be succeeded by repeated full submission validation of the same Captcha code, the AjaxValidate call doesn't delete successfully validated Captcha codes (but does delete codes the validation of which failed).

This function is available to make it easier to integrate BotDetect Captcha validation with all manners of custom Ajax validation approaches and frameworks. You don't need to call it when using regular Captcha validation or the built-in BotDetect Ajax Captcha validation functionality.

Has the current Captcha instance been successfully validated already.

Captcha code length, in characters.

Captcha code style (alphanumeric, alpha, or numeric).

Captcha code timeout in seconds - the Captcha can only be successfully solved within the specified time after generation.

This is an optional security improvement that narrows the window of opportunity for attacks based on re-using the Captcha image on another site controlled by the attacker, or similar human-solver-based attacks on Captcha-protected forms.

Defines rules about character sequences you want to avoid using in randomly generated CAPTCHA codes. Must be a CSV string.

Captcha image style - can be a fixed or a randomized value selected from the 60 BotDetect image drawing algorithms.

Captcha image width, in pixels.

Captcha image height, in pixels.

Captcha image output format (Jpeg, Gif or Png).

Used to override the default Captcha image color scheme. Html named or hex color value of the dark color used in Captcha images.

Used to override the default Captcha image color scheme. Html named or hex color value of the light color used in Captcha images.

Is Captcha sound enabled.

Captcha sound style - can be a fixed or a randomized value selected from the 10 BotDetect sound generation algorithms.

Captcha sound output format (WavPcm16bit8KhzMono or WavPcm8bit8KhzMono).

BotDetect audio Captcha sound regeneration mode determining how will multiple consecutive requests for audio Captcha with the same Captcha code be handled by BotDetect.

If the required SoundPackage in not deployed, the sound icon is not clickable and displays a warning tooltip by default.

If you want to disable this warning and simply not display the sound Captcha icon at all for locales whose pronunciations are not deployed with the application, set this property to false.

Captcha locale string, affecting the charset used for Captcha code generation, and the pronunciation language used for sound Captchas.

Custom Captcha image alt text / title.

Custom sound Captcha icon alt text / title.

Custom reload Captcha icon alt text / title.

Url to which the Captcha help link points to.

Text used in the Captcha help link; leave empty for default image width-dependent text.

Is Captcha reloading enabled.

Url of the Captcha reload icon; can be a relative or an absolute Url pointing to the icon of your choice

Url of the Captcha sound icon; can be a relative or an absolute Url pointing to the icon of your choice

Is the Captcha help link enabled or not.

Controls how the Captcha help link is displayed; supported modes are HelpLinkMode::Image and HelpLinkMode::Text.

Anything the users type in the input textbox will be uppercased on the fly, since Captcha validation is not and should not be case-sensitive.

This is a small usability improvement that helps communicate that fact to the users clearly.

The input textbox will be assigned focus on all Captcha Sound and Captcha Reload icon clicks, allowing the users to more easily type in the code as they hear it or as the new image loads.

This does not apply to auto-reloading of expired Captchas, since the user might be filling out another field on the form when the auto-reload starts and shouldn't be distracted.

The input textbox will be cleared on all Reload icon clicks and auto-reloads, since any previous input in the textbox will be invalidated by Captcha reloading.

This is a small usability improvement that helps users avoid having to delete the previous input themselves.

Captcha images are automatically reloaded when the Captcha code expires (as set in the CodeTimeout element, or the ASP Session timeout), but only within a certain interval from their first generation.

This allows you to have a short Captcha code timeout (e.g. 2 minutes) to narrow the window of opportunity for Captcha reusing on other sites or human-solver-powered bots, and actual visitors can still fill out your form at their own pace and without rushing (since the Captcha image will be reloaded automatically when it is no longer valid).

Since we don't want infinite sessions when the user leaves the form open in a background browser tab over the weekend (for example), we set a reasonable upper limit on the auto-reload period (e.g. 2 hours = 7200 seconds).

Captcha sound JavaScript playback starting delay, in milliseconds.

By default, BotDetect also adds a remote JavaScript include loaded from the captcha.com server, which is currently used only for stats, but is planned to develop into additional Captcha functionality. This include can be disabled using this configuration property.

For custom integrations into 3rd party frameworks, it might be necessary to modify the base Url of Captcha image and sound requests, which can be achieved using this configuration setting