JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <select multiple='multiple' data-bind="options: myList, optionsText: 'name', optionsValue: 'id' "></select>
    <select multiple='multiple' data-bind="options: myOtherList, optionsText: 'name',
optionsValue: 'id' "></select>
    <button data-bind="click: someFunction">Click me</button>
</body>

JavaScript

var vm = function() {
    var self = this;
    
    self.someFunction = function() {
        alert('hello');
    };
    
    self.myList = ko.observableArray();
    
    self.myList.push({ id: 1
                      , name: 'Option 1'
                     });
    self.myList.push({ id: 2
                      , name: 'Option 2'
                     });
    self.myList.push({ id: 3
                      , name: 'Option 3'
                     });
    self.myOtherList = ko.observableArray();
    self.myOtherList.push({ id: 0
                           , name: 'Option 0'
                          });
}

if (window.addEventListener) {
    window.addEventListener('load', function() {
        var viewModel = vm();
        ko.applyBindings(viewModel);
    }, false); // NB **not** 'onload'
} else if (window.attachEvent) {
    window.attachEvent('onload', function () {
        var viewModel = vm();
        ko.applyBindings(viewModel);
    });
}