title: Birthday dropdown list
body: <p>I want user to enter his birthday from dropdown menu during registration.I searched for code and got this</p>
  
  <pre><code>    &lt;tr&gt;
        &lt;td&gt;&lt;label&gt;Birthday:&lt;/label&gt;&lt;/td&gt;
        &lt;td&gt;
          &lt;div class="input-container"&gt;
          &lt;select name="month"&gt;&lt;option value="0"&gt;Month:&lt;/option&gt;&lt;?=generate_options(1,12,'callback_month')?&gt;&lt;/select&gt;
          &lt;select name="day"&gt;&lt;option value="0"&gt;Day:&lt;/option&gt;&lt;?=generate_options(1,31)?&gt;&lt;/select&gt;
          &lt;select name="year"&gt;&lt;option value="0"&gt;Year:&lt;/option&gt;&lt;?=generate_options(date('Y'),1900)?&gt;&lt;/select&gt;
          &lt;/div&gt;
        &lt;/td&gt;
      &lt;/tr&gt;
  </code></pre>
  
  <p>But this code is not working.Please show some error or provide with better dropdown menu code.</p>