Struktur Fata Stack

?html>
?head>
?title>Stuktur Fata stack?/title>
?script language = "JavaScript">

var stack = new Array ();
function Input_ke_Stack (data) {
stack.push(data);
}

function Ambil_dari_Stack() {
var data_dari_stack = stack.pop();
if (data_dari_stack == undefined)
return "Stack Sudah Kosong";
else
return data_dari_stack;
}

function TampilkanStack(list){
list.options.length = 0;
for (var i = 0; i < stack.length; i++) {
var data = new Option(stack[i]);
list.options[list.options.length] = data;
}
}
?/script>
?/head>
?body>
?form>
?input type=text name=textSimpan>
?input type=button value="Masukan ke Stack"
onClick='Input_ke_Stack(textSimpan.value);
textSimpan.value=""; TampilkanStack(mediaList);'>
?select name="mediaList" size=12>
?option>Tampilan data....
?/select>
?input type=text name=textAmbil size=20>
?input type=button value="Ambil dari Stack"
onClick="textAmbil.value = Ambil_dari_Stack();
TampilkanStack(mediaList);">
?/form>
?/body>
?/html>