Batch edit item language to de for German items

gistfile1.txt

var fieldName = "title";
var fieldName2 = "language";
var oldValue = "für";
var newValue = "de";
 
var fieldID = Zotero.ItemFields.getID(fieldName);
var fieldID2 = Zotero.ItemFields.getID(fieldName2);
var s = new Zotero.Search;
s.addCondition(fieldName, 'contains', oldValue);
s.addCondition("itemType", 'isNot', "attachment"); 
var ids = s.search();
if (ids) {
	for each(var id in ids) {
		var item = Zotero.Items.get(id);
		var mappedFieldID = Zotero.ItemFields.getFieldIDFromTypeAndBase(item.itemTypeID, fieldName2);
		item.setField(mappedFieldID ? mappedFieldID : fieldID2, newValue);
		item.save();
	}
	alert(ids.length + " items updated");
}
else {
	alert("No items found");
}