title: Clear text box after choose certain option on select box
body: <p>I have a select box and text box like this :</p>
  
  <pre><code>&lt;?php
      $receipt="12345";
  ?&gt;
  
  &lt;form&gt;
      &lt;select name="sent" id="sent"&gt;            
          &lt;option value="1"&gt;Yes&lt;/option&gt;
          &lt;option value="0"&gt;No&lt;/option&gt;
      &lt;/select&gt; 
  
      &lt;input type="text" name="receipt" value="&lt;?=$receipt?&gt;"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>how can I clear the textbox after I choose option <strong>No</strong> ?</p>