JSFiddle - React, Tailwind, and code Playground

HTML

<select id='fileBox' name='fileBox'>
<option value="http://www.google.com">Google</option>
<option value='http://www.google.com'>File2.pdf</option>
<option value='http://www.google.com'>File3.pdf</option>
</select>
<input type="button" value="Open File" id="linkButton" />

JavaScript

var btn = document.getElementById('linkButton');
btn.addEventListener('click',GetInfo,false);

function GetInfo(){
var e = document.getElementById("fileBox");
var selectedUrl = e.options[e.selectedIndex].value;
window.open(selectedUrl);  
}