Add div that I was supposed to add earlier

compare-betas.html

@@ -9,6 +9,7 @@
 <select name="beta1" id="beta1"></select>
 <select name="beta2" id="beta2"></select>
 <button id="compareButton">Compare</button>
+<div id="warning" style="font-weight: bold; color: red;"></div>
 <br><br>
 <iframe id="frame" src="about:blank" width="100%" style="height: 100%; border: none;"></iframe>
 </body>