JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cloud.github.com/downloads/SteveSanderson/knockout/knockout-2.1.0.js"></script>
<div data-bind='foreach: {data:items, afterAdd:enter}'>
    <div data-bind='text:$data'> </div>
</div>
<button id="add">Add Another</button>

JavaScript

var vm = {
    items: ko.observableArray(['one', 'two', 'three']),
    enter: function(elem) {
        if (elem.nodeType === 1) 
            $(elem).hide().slideDown('fast'); 
    }
};

$("#add").click(function() {
    vm.items.push('another');
});
 
ko.applyBindings(vm);