title: PHP POST missing radio button from HTML form
body: <p>It's such simple code but I can't figure out what is wrong with it. All other input from the form exists, except radio buttons. </p>
  
  <p>This is my form:</p>
  
  <pre><code>&lt;form action="&lt;?php echo htmlspecialchars($_SERVER['PHP_SELF']);?&gt;"
        method="POST"&gt;
    &lt;div class="form-group"&gt;
      &lt;label&gt;Username&lt;/label&gt;
      &lt;input class="form-control" type="text" name="username"&gt;
      &lt;span class="errorMsg"&gt; &lt;?php echo $usernameErr; ?&gt;&lt;/span&gt;
    &lt;/div&gt;
    &lt;div class="form-group"&gt;
      &lt;label&gt;Password&lt;/label&gt;
      &lt;input class="form-control" type="password" name="password1"&gt;
      &lt;span class="errorMsg"&gt; &lt;?php echo $passwordErr; ?&gt;&lt;/span&gt;
      &lt;label&gt;Confirm Password&lt;/label&gt;
      &lt;input class="form-control" type="password" name="password2"&gt;
      &lt;span class="errorMsg"&gt; &lt;?php echo $confirmPasswordErr; ?&gt;&lt;/span&gt;
    &lt;/div&gt;
    &lt;hr&gt;
    &lt;div class="form-group"&gt;
      &lt;label&gt;E-mail&lt;/label&gt;
      &lt;input class="form-control" type="email" name="email"&gt;
      &lt;span class="errorMsg"&gt; &lt;?php echo $emailErr; ?&gt;&lt;/span&gt;
    &lt;/div&gt;
    &lt;div class="form-group"&gt;
      &lt;label class="radio-inline"&gt;
        &lt;input type="radio" name="gender" value="m"&gt; Male
      &lt;/label&gt;
      &lt;label class="radio-inline"&gt;
        &lt;input type="radio" name="gender" value="f"&gt; Female
      &lt;/label&gt;
      &lt;span class="errorMsg"&gt; &lt;?php echo $genderErr; ?&gt;&lt;/span&gt;
    &lt;/div&gt;
    &lt;div class="form-group"&gt;
      &lt;button class="btn btn-default" type="submit" name="submitted"&gt;Submit&lt;/button&gt;
    &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>This is PHP part:</p>
  
  <pre><code>&lt;?php
    if (isset($_POST['submitted'])) {
      $min = 5;
      $max = 10;
  
      $username = $_POST['username'];
      $password = $_POST['password1'];
      $confirmPassword = $_POST['password2'];
      $email = $_POST['email'];
      $gender = $_POST['gender'];
      echo "----------------------";
      print_r($_POST);
    }
  ?&gt;
  </code></pre>
  
  <p>And what it shows:</p>
  
  <pre><code>array(5) { ["username"]=&gt; string(0) "" ["password1"]=&gt; string(0) "" ["password2"]=&gt; string(0) "" ["email"]=&gt; string(0) "" ["submitted"]=&gt; string(0) "" } 
  </code></pre>
  
  <p>Why am I not seeing ["gender"] in it? </p>