FlexCaptcha

Protect your ASP.NET forms using professional Captcha for free.

FlexCaptcha was developed as part of the amazing Discussions control and is likely the most advanced freeware captcha control in existence.

FlexCaptcha supports captchas written to either disk or directly to http stream, which makes FlexCaptcha usable in a broader context. In addition FlexCaptcha is reliable, very versatile and have commercial quality.

FlexCaptcha Key Features

FlexCaptcha can write to either disk (works out of the box) or directly to http stream (faster but you need to register an http handler in web.config).
Multiple Captcha's on the same page.
Optional include of user input box (if including user intput box you can also css style the box).
Optional include of ajax reload captcha button (if including reload you can also substitute the default reload images).
Multiple character sets including option for a custom character set
Many other standard captcha configural handles - making it easy to customize the Captcha experience.
Visual Studio design support.
Several online examples with code.
Compiled as backward compatible the whole way back to .net framework 2.0
Commercial quality as freeware.

RichTextBox Examples

FlexCaptcha formal documentation
FlexCaptcha history
FlexCaptcha examples :
- Default - you can reference this example the same way as you reference the documentation
- Image mode - write to disk or directly to http stream
- Setting Sizes
- Letter Sets
- Brushes & Colors
- Elements to Include

How to use FlexCaptcha

Download FlexCaptcha, unzip it and add it to your asp.net website bin folder.

<%@ Register Assembly="Menulab.FlexCaptcha" Namespace="Menulab" TagPrefix="ml" %>

Add a FlexCaptcha instance somewhere on your page (or on a usercontrol) :
```
<ml:FlexCaptcha ID="mlFlexCaptcha" runat="server" />
```

Add an asp submit button :

<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />

In the code-behind file add the submit buttons Click handler :
```
protected void btnSubmit_Click(object sender, EventArgs e)
{
	bool captchaIsValid = mlFlexCaptcha.mlValidate();
}
```
Note : you can also add FlexCaptcha to Visual Studio Toolbox and drag the control to your page in which case the above step 2 & 3 will be automatically done for you.