PHP Basic CAPTCHA Code Sample (BotDetect v3.0; deprecated)

First Time Here?

Check the BotDetect PHP Captcha Quickstart for key integration steps.

The PHP Basic Captcha code sample shows the most basic source code required to protect a PHP form with BotDetect CAPTCHA and validate the user input.

It can be used as a starting point when you are first learning how to use BotDetect.

Downloaded Location

The PHP basic Captcha code sample is included in the samples/php_basic_captcha_sample folder of the download package.

index.php

index.php

<?php session_start(); ?>
<?php require("botdetect.php"); ?>
<!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 PHP CAPTCHA Basic Sample</title>
  <link type="text/css" rel="Stylesheet" href="StyleSheet.css" />
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  <link type="text/css" rel="Stylesheet" 
    href="<?php echo CaptchaUrls::LayoutStylesheetUrl() ?>" />
</head>
<body>
  <form method="post" action="" id="form1">

    <h1>BotDetect PHP CAPTCHA Basic Sample</h1>
    
    <fieldset>
      <legend>PHP CAPTCHA validation</legend>
      <label for="CaptchaCode">Retype the characters from the picture:
      </label>
      
      <?php // Adding BotDetect Captcha to the page 
        $SampleCaptcha = new Captcha("SampleCaptcha");
        $SampleCaptcha->UserInputID = "CaptchaCode";
        echo $SampleCaptcha->Html(); 
      ?>
      
      <div class="validationDiv">
        <input name="CaptchaCode" type="text" id="CaptchaCode" />
        <input type="submit" name="ValidateCaptchaButton" 
          value="Validate" id="ValidateCaptchaButton" />
        
        <?php // when the form is submitted
          if ($_POST) { 
            // validate the Captcha to check we're not dealing with a bot
            $isHuman = $SampleCaptcha->Validate();
            
            if (!$isHuman) {
              // Captcha validation failed, show error message
              echo "<span class=\"incorrect\">Incorrect code</span>";
            } else {
              // Captcha validation passed, perform protected action
              echo "<span class=\"correct\">Correct code</span>";
            } 
          }
        ?>
      </div>
    </fieldset>
  </form>
</body>
</html>

After Captcha object instance and printing the Html function result. The same object instance provides easy Captcha validation using the Validate function.

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