This is an HTML and CSS question, and here is the code.
* { margin:0; padding:0; }
TABLE { border-collapse:collapse; border-width:0px; }
TD DIV { width:450px; height:450px; overflow:hidden; }
<table>
<tr>
<td>
<div>Hi! This is a big long string of text.</div>
</td>
<tr>
</table>
I just gave the generic tag names but if that breaks your design then rename.
Alternatively you can use the code to scroll the contents of the DIV, just make sure you adjust the width to account for the Scroll Bar that will show up, they are usually around 16px.
TD DIV { width:434px; height:450px; overflow:scroll; }