Textarea Overflow

I have a mini chat on my website and i want to avoid stripping inputs from html and php tags so i made all inputs appear inside textareas.
Here is a test piece of code:

<?php$originaltext="x<br>s<br>s<br>s<br>s<br>s<br>s<br>s<br>s<br>s<br>s<br>s";$fixedtext = str_replace("<br>", "\n", $originaltext);  //turn the <br>s into new lines inside textareasecho "<textarea style=\"background:black;color:white;border:0px;overflow:visible;\"  >".$fixedtext."</textarea>";?>

the overflow has no effect on google chrome or firefox but has effect on internet explorer, how do i make it work on other browsers?

on a side question can i strip the effect (effect not the syntax) from divisions? i can deal with them better than text areas.
meaning if you put

<table><tr><td>s</td></tr></table>

as in input inside chat it will appear the same, no effect.. just like if it is shown inside a text area.