Change the options array of a select list

Question

Is there a way to change the options array of an html select list using javascript or mootools?

I need to replace the entire options set with a new one. In my ajax

Answer 1

Vanilla JS solution

var arrOptions = [];
arrOptions.push("Select from List...");
arrOptions.push("Trust Deposit");
arrOptions.push("Operating Deposit");

document.getElementById("selectInput").innerHTML = arrOptions.join();

If you already have a set of options

var arrOptions = [];
var arrOptionsCollection = document.getElementById("check_typeInput").options;
for (var i=0, n = arrOptionsCollection.length; i < n; i++) { // looping over the options
    if (arrOptionsCollection[i].value) {
        arrOptions.push("" + arrOptionsCollection[i].text + "");
    }
}
arrOptions.push("Trust Deposit");
arrOptions.push("Operating Deposit");

document.getElementById("selectInput").innerHTML = arrOptions.join();