dijit/registry.findWidgets
HTML
<link rel="stylesheet" href="https://ajax.googleapis.com/ajax/libs/dojo/1.10.4/dojo/resources/dojo.css">
<link rel="stylesheet" href="https://ajax.googleapis.com/ajax/libs/dojo/1.10.4/dijit/themes/tundra/tundra.css">
<body class="tundra">
<div id="container">
<input data-dojo-type="dijit/form/NumberTextBox"></input>
</div>
<div id="empty"></div>
</body>
JavaScript
require([
'dijit/registry',
'dojo/dom',
'dojo/parser',
'dijit/form/NumberTextBox',
'dijit/registry',
'dojo/domReady!'
], function(registry, dom, parser) {
parser.parse();
console.log(registry.findWidgets(formNode));
console.log(registry.findWidgets(dom.byId('container')));
console.log(registry.findWidgets(dom.byId('empty')));
});