GAS - Dropdown List In Google Form -

i'm trying add items 'listitem' spreadsheet displayed whenever user enters google form.

copied google developer reference,

var form = formapp.openbyid('1234567890abcdefghijklmnopqrstuvwxyz'); var item = form.addlistitem(); item.settitle('do prefer cats or dogs?'); item.setchoicevalues(['dogs', 'cats']); 

how loop add in items? current code below flawed.

var items = form.getitems(); var item = items[1]; var itemlist = item.aslistitem(); var ss = spreadsheetapp.openbyid("123456").getsheetbyname('list').getdatarange().getvalues(); (var = 1; < ss.length; i++){     var row = teacherss[i];     itemlist.setchoices([row[i]]); } 

for adding values listitem, can way

function testadding(){ var form = formapp.getactiveform(); var item = form.addlistitem(); item.settitle('do prefer cats or dogs?');  var ss = spreadsheetapp.openbyid("123456").getsheetbyname('list').getdatarange().getvalues(); item.setchoicevalues(ss);  } 

if want add listitem on form open, can try using triggers.

hope helps!