jQuery Hiding or showing a input box
<p>I am getting confused with the different ways that people have mentioned on here on how to do the following:</p>

<p>I have a dropdown menu <code>add_fields_placeholder</code> with three values: </p>

<ul>
<li>Please Select - <code>value=""</code></li>
<li>Yes - <code>value ="yes"</code></li>
<li>No - <code>value = "no"</code>  </li>
</ul>

<p>Below this I have an input box called <code>add_fields_placeholderValue</code></p>

<p>How could I make this input "required" but also visible if the above is selected to yes?</p>
