document.getElementById(id)的隱藏與顯示

<script language="javascript">
var n = 1;
function $(id){ 
 return document.getElementById(id);
}
function show_child(){
if(n==1){
//alert(n);
$("rwgl").style.display="none";
n = n-1;
}
else {
//alert("");
$("rwgl").style.display="block";
n = n+1;
}
}
</script>