<input class="first-name" type="text">
<input class="last-name" type="text">

<output class="last-name"></output>

<script src="matreshka.min.js"></script>
<script>
var app = new Matreshka();

app.bindNode({
    firstName: 'input.first-name',
    lastName: 'input.last-name',
    fullName: 'output.full-name'
})
.linkProps('fullName', 'firstName lastName', function(firstName, lastName) {
    return firstName + ' ' + lastName;
});

app.firstName = 'Brendan';
app.lastName = 'Eich';

alert(app.fullName);
</script>

<script src="https://cdn.jsdelivr.net/matreshka/latest/matreshka.min.js"></script>