How to create small Jquery Plugin to change list to drop down when screen size changes from desktop to phone screen

I am trying to create a custom Jquery Plugin to replace the list with Drop down Menu when size changes to phone.. Not able to proceed further...

[JSfiddle link][1]https://jsfiddle.net/Shivanigupta/6o5fw66f/16/

     <nav>  
      <select class="tabMenu">
       <option value="tab1Content">Tab1</option>
       <option value="tab2Content">Tab2</option>
       <option value="tab3Content">Tab3</option>
     </select>
    <ul id="tabContent">
      <li class='active'><a href='#tab1Content'>Tab1</a></li>
      <li><a href='#tab2Content'>Tab2</a></li>
    <li><a href='#tab3Content'>Tab3</a></li>
    </ul> 
 </nav>