<table border=0 width=270 id="myexample"
style="border:2px solid yellow">
<tr>
<td>Ваш текст
</td>
</tr>
</table>

<script language="JavaScript">
<!--
function flashit()
{
if (!document.all)return;
if (myexample.style.borderColor==
   "yellow")myexample.style.borderColor="lime";
else myexample.style.borderColor=
   "yellow"}setInterval("flashit()", 1000)
//-->
</script>