DevExtreme Validator

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/knockout/3.1.0/knockout-min.js"></script>
<script src="http://ajax.aspnetcdn.com/ajax/globalize/0.1.1/globalize.min.js"></script>
<link rel="stylesheet" href="http://cdn3.devexpress.com/jslib/14.2.3/css/dx.common.css">
<link rel="stylesheet" href="http://cdn3.devexpress.com/jslib/14.2.3/css/dx.light.css">
<script src="http://cdn3.devexpress.com/jslib/14.2.5/js/dx.phonejs.js"></script>
<div id="textbox"></div>

JavaScript

$(function() {
    $("#textbox")
        .dxTextBox({
            valueUpdateEvent: "keyup input"
        })
        .dxValidator({
            validationRules: [{
                type: "required",
                message: "Value is required"
            }]
        });
});