Edit in JSFiddle

var viewModel = {
    name: ko.observable("World")
};

ko.applyBindings(viewModel);

<div data-bind="template: 'Tmpl'"></div>

<script id="Tmpl" type="text/html">
    Hello ${name}!
    <br />
    <input data-bind="value: name, valueUpdate: 'keyup'" />
</script>