Canvas Combobox Component how to set Values with Javascript

I have got a solution to append a value and text.

$('#combo1').
append($("<option/>").
attr("value",'No 1').
text('Jimi Hendrix'));

This page helped me

https://techbrij.com/jquery-operations-on-dropdownlist-combobox

Even if I want to set new Values und delete the former values I can use this script:

var str = "<option value='0'>Hund</option><option value='1'>Katze</option>";
$('#combo1').html(str);