CSS: how can I force a long string (without any blank) to be wrapped in XUL and/or HTML

<textarea style="border:1px solid red; width:100px;word-wrap:break-word;">AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA</textarea>

ACTGATCG&shy;AGCTGAAG&shy;CGCAGTGC&shy;GATGCTTC&shy;GATGATGC&shy;TGACGATG

<td width="170px" style="word-wrap:break-word;">

</div></td>