appendItem

例

<script language="javascript">
function addItemsToList(){
	var list = document.getElementById('myMenuList');

	// add item with just the label
	list.appendItem('One');

	// add item with label and value
	list.appendItem('Two', 999);

	// Select the first item
	list.selectedIndex = 0;
}
</script>

<button label="Add items" oncommand="addItemsToList()"/>
<menulist id="myMenuList">
  <menupopup/>
</menulist>

参照

insertItemAt(), removeItemAt()