title: Copy selected multiple values to the text box
body: <p>I have drop down list as below. </p>
  
  <pre><code>     &lt;select id="checkOwner" multiple="multiple" onchange="copyValue()"&gt;
         &lt;option value="FIRSTNAME"&gt;First Name&lt;/option&gt;
         &lt;option value="LASTNAME"&gt;Last Name&lt;/option&gt;
       &lt;/select&gt;
  </code></pre>
  
  <p>I used Below javascript to add checkbox </p>
  
  <pre><code>$(function() {
    $('#checkOwner').multiselect({
     });  
  });
  </code></pre>
  
  <p>I used below javascript to copy selected value to text field.</p>
  
  <pre><code>function copyValue() {
    var dropboxvalue = document.getElementById('checkOwner').value;
    document.getElementById('mytextbox').value = dropboxvalue;
  }
  </code></pre>
  
  <p>But the problem is, this copy only one value. I want to copy all the selected values. How can I do this?</p>