title: Remove selected option from another select box
body: <p>I am trying implement multiple select boxes in a single page. All these select boxes will have the same option values. When I select first option from select box 1, then that option should be removed from remaining select boxes.</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;select name="selectBox1" id="selectBox1"&gt;
     &lt;option value="option1"&gt;option1&lt;/option&gt;
     &lt;option value="option2"&gt;option2&lt;/option&gt;
     &lt;option value="option3"&gt;option3&lt;/option&gt;
     &lt;option value="option4"&gt;option4&lt;/option&gt; 
  &lt;/select&gt;
  
  &lt;select name="selectBox2" id="selectBox2"&gt;
      &lt;option value="option1"&gt;option1&lt;/option&gt;
      &lt;option value="option2"&gt;option2&lt;/option&gt;
      &lt;option value="option3"&gt;option3&lt;/option&gt;
      &lt;option value="option4"&gt;option4&lt;/option&gt;    
  &lt;/select&gt;
  
  &lt;select name="selectBox3" id="selectBox3"&gt;
      &lt;option value="option1"&gt;option1&lt;/option&gt;
      &lt;option value="option2"&gt;option2&lt;/option&gt;
      &lt;option value="option3"&gt;option3&lt;/option&gt;
      &lt;option value="option4"&gt;option4&lt;/option&gt;    
  &lt;/select&gt;
  </code></pre>
  
  <p>How do I do it? I know how to remove or add option if there is only one select box, but for multi select box, I am stuck.</p>