<script language="JavaScript">
function chVis(){
el=document.getElementById("pun-announcement").getElementsByTagName("div")[2]
if(el.style.display!="none"){
el.style.display="none"
document.getElementById("annBut").value="Показать"
}
else {
el.style.display="inline"
document.getElementById("annBut").value="Скрыть"
}
}
elm=document.getElementById("pun-announcement")
elm.style.position="relative"
elm.innerHTML="<div style='position: absolute; top: 10px; right: 20px;'><input id=annBut type=\"Button\" value='Скрыть' onclick='chVis()'></div>"+elm.innerHTML
</script>