title: Set an existing dropdown as multiselect dynamically
body: <p>I want so set an existing dropdown as multi-select dynamically</p>
  
  <p>I have a Dropdown</p>
  
  <pre><code>&lt;select id='ddSelect'&gt;
    &lt;option value="volvo"&gt;Volvo&lt;/option&gt;
    &lt;option value="saab"&gt;Saab&lt;/option&gt;
    &lt;option value="opel"&gt;Opel&lt;/option&gt;
    &lt;option value="audi"&gt;Audi&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>I want to set <code>#ddSelect</code> as multiselect. </p>
  
  <p>Is there any option like <code>$('#ddSelect').attr('multiple').val('true')</code> or something?</p>
  
  <p>Is that possible via jQuery or Javascript?</p>