JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdn.ractivejs.org/latest/ractive.js"></script>
<main></main>

<script id='template' type='text/ractive'>
    <p>try typing a string in here. It should be coerced to a number or replaced with <code>undefined</code>, but it gets overridden on blur...</p>
    <input value='{{foo}}'/>
    <p>{{typeof foo}}: [{{foo}}]</p>
</script>

CSS

body {
    font-family: 'Helvetica Neue', arial, sans-serif;
    font-weight: 200;
    color: #353535;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 200;
}

JavaScript

var ractive = new Ractive({
    el: 'main',
    template: '#template',
    data: { foo: '42' }
});

// emulate type='number' coercion
ractive.observe( 'foo', function ( foo ) {
    var number = parseFloat(foo);
    this.set( 'foo', isNaN(number) ? undefined : number );
});