title: How to sum values of selected options?
body: <p>I have 3 selectors, all selectors have some options with some values.</p>
  <p>How do I sum all values of selected options?</p>
  <pre class="lang-html prettyprint-override"><code>&lt;select name='anch1'&gt;
      &lt;option value='10'&gt;10 ++&lt;/option&gt;
      &lt;option value='20'&gt;20 ++&lt;/option&gt;
      &lt;option value='30'&gt;30 ++&lt;/option&gt;
      &lt;option value='40'&gt;40 ++&lt;/option&gt;
      &lt;option value='50'&gt;50 ++&lt;/option&gt;
  &lt;/select&gt;
  
  &lt;select name='anch2'&gt;
      &lt;option value='10'&gt;10 ++&lt;/option&gt;
      &lt;option value='20'&gt;20 ++&lt;/option&gt;
      &lt;option value='30'&gt;30 ++&lt;/option&gt;
      &lt;option value='40'&gt;40 ++&lt;/option&gt;
      &lt;option value='50'&gt;50 ++&lt;/option&gt;
  &lt;/select&gt;
      
  &lt;select name='anch3'&gt;
      &lt;option value='10'&gt;10 ++&lt;/option&gt;
      &lt;option value='20'&gt;20 ++&lt;/option&gt;
      &lt;option value='30'&gt;30 ++&lt;/option&gt;
      &lt;option value='40'&gt;40 ++&lt;/option&gt;
      &lt;option value='50'&gt;50 ++&lt;/option&gt;
  &lt;/select&gt;
      
  &lt;div&gt;SUM OF SELECTED OPTIONS&lt;/div&gt;
  </code></pre>