WebPlus X6: javascript text properties

how do i change the size, color, font.... whatever to this javascript code:

<script type="text/javascript">

<!--
var m = "Última atualização: " + document.lastModified;
var p = m.length-8;
document.writeln("<center>");
document.write(m.substring(p, 0));
document.writeln("</center>");
-->
</script>

thanks