JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.jquery.com/jquery-1.9.1.js"></script>

<form name="input" method="post" action="#">
Display Tag:<input id="texthere" type="text" name="taginput">
<input type="submit" value="Go">
<select name="tags" multiple>
    <option value="C#">C#</option>
   <option value="Java">Java</option>
    <option value="Javascript">Javascript</option>
    <option value="PHP">PHP</option>
    <option value="Android">Android</option>
    <option value="jQuery">jQuery</option>
    <option value="C++">C++</option>
    <option value="Python">Python</option>
    <option value="HTML">HTML</option>
    <option value="MySQL">MySQL</option>
</form>

JavaScript

$('select option').on('click',function(){
    $('#texthere').val( $(this).attr('value') );
});