title: jQuery multiselect just to copy from one select box to another one
body: <p>Here am using jquery multiselect. When I click on a item it is moving from one select box to another one, but I need just to copy from a select box to another one. I want clicked item always available to left select box. Any suggestions? </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$(document).ready(function() {
    $('#undo_redo').multiselect();
  });</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="https://www.jqueryscript.net/css/jquerysctipttop.css" rel="stylesheet" type="text/css"&gt;
  &lt;link rel="stylesheet" href="https://netdna.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css"&gt;
  &lt;script src="https://code.jquery.com/jquery-1.11.2.min.js"&gt;&lt;/script&gt;
  &lt;script src="https://netdna.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"&gt;&lt;/script&gt;
  &lt;script src="https://www.jqueryscript.net/demo/Two-side-Multi-Select-Plugin-with-jQuery-multiselect-js/js/multiselect.js"&gt;&lt;/script&gt;
  &lt;div class="container"&gt;
    &lt;h1 style="margin:10px auto 50px auto; text-align:center"&gt;jQuery multiselect.js Example&lt;/h1&gt;
    &lt;div class="row"&gt;
      &lt;div class="col-xs-5"&gt;
        &lt;select name="from" id="undo_redo" class="form-control" size="13" multiple="multiple"&gt;
          &lt;option value="1"&gt;C++&lt;/option&gt;
          &lt;option value="2"&gt;C#&lt;/option&gt;
          &lt;option value="3"&gt;Haskell&lt;/option&gt;
          &lt;option value="4"&gt;Java&lt;/option&gt;
          &lt;option value="5"&gt;JavaScript&lt;/option&gt;
          &lt;option value="6"&gt;Lisp&lt;/option&gt;
          &lt;option value="7"&gt;Lua&lt;/option&gt;
          &lt;option value="8"&gt;MATLAB&lt;/option&gt;
          &lt;option value="9"&gt;NewLISP&lt;/option&gt;
          &lt;option value="10"&gt;PHP&lt;/option&gt;
          &lt;option value="11"&gt;Perl&lt;/option&gt;
          &lt;option value="12"&gt;SQL&lt;/option&gt;
          &lt;option value="13"&gt;Unix shell&lt;/option&gt;
        &lt;/select&gt;
      &lt;/div&gt;
      &lt;div class="col-xs-2"&gt;
        &lt;button type="button" id="undo_redo_undo" class="btn btn-primary btn-block"&gt;undo&lt;/button&gt;
        &lt;button type="button" id="undo_redo_rightAll" class="btn btn-default btn-block"&gt;&lt;i class="glyphicon glyphicon-forward"&gt;&lt;/i&gt;&lt;/button&gt;
        &lt;button type="button" id="undo_redo_rightSelected" class="btn btn-default btn-block"&gt;&lt;i class="glyphicon glyphicon-chevron-right"&gt;&lt;/i&gt;&lt;/button&gt;
        &lt;button type="button" id="undo_redo_leftSelected" class="btn btn-default btn-block"&gt;&lt;i class="glyphicon glyphicon-chevron-left"&gt;&lt;/i&gt;&lt;/button&gt;
        &lt;button type="button" id="undo_redo_leftAll" class="btn btn-default btn-block"&gt;&lt;i class="glyphicon glyphicon-backward"&gt;&lt;/i&gt;&lt;/button&gt;
        &lt;button type="button" id="undo_redo_redo" class="btn btn-warning btn-block"&gt;redo&lt;/button&gt;
      &lt;/div&gt;
      &lt;div class="col-xs-5"&gt;
        &lt;select name="to" id="undo_redo_to" class="form-control" size="13" multiple="multiple"&gt;&lt;/select&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
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  </p>