title: javascript/jquery generate input element
body: <p>So I have this code. And I want to accomplish something
  probably simple for javascript guys. If a certain option is selected
  then add an input field on a div.</p>
  
  <pre><code>&lt;select name="amount" &gt;
      &lt;option value="50"&gt;50$&lt;/option&gt;
      &lt;option value="100"&gt;100$&lt;/option&gt;
      &lt;option value="Other"&gt;Other&lt;/option&gt;
  &lt;/select&gt;
  
  &lt;div id="custom_price"&gt;
  
  &lt;/div&gt;
  </code></pre>
  
  <p>So I want to add the input field once the <strong>'Other'</strong> option is selected. I know there's
  a simple way around this but I cannot make it work:</p>
  
  <pre><code>document.getElementById('custom_price').innerHTML += "&lt;input type="text" name="amount"/&gt;"
  </code></pre>
  
  <p>So custom_div would look like:</p>
  
  <pre><code>&lt;div id="custom_price"&gt;
  Custom price:&lt;br&gt;
  &lt;input type="text" name="amount"/&gt;
  &lt;/div&gt;
  </code></pre>