Scroll Box Coding Help

So currently I am working on trying to get scroll boxes to work on my den page but the "overflow:auto" command consistently disappears every time I save my code to check if it's working. As of now I keep ending up with just two standard boxes with no scroll.

Here's my coding:

<div style="height:200px;width:43%;border:5px solid #000000;padding:2%;float:left;overflow:auto;">TEST</div></div>

<div style="height:200px;width:43%;border:5px solid #000000;padding:2%;float:right;overflow:auto;">TEST</div>

Any help/insight is appreciated!