¥function addItem() {
¥ var listbox =
document.getElementById("itemlist");
¥ var listitem =
document.createElement("listitem");
¥ var labelfield =
document.getElementById("labelfield");
¥ listbox.appendChild(listitem);
¥ listitem.label = labelfield.value;
¥ labelfield.value = "";
¥ validateInput();
¥ labelfield.focus();
¥}
¥
¥function validateInput() {
¥ var field =
document.getElementById("labelfield");
¥ var button =
document.getElementById("addButton");
¥ button.disabled = field.value == "";
¥}