JavaScript DHTML/Dojo toolkit/setObject
dojo.setObject
<html>
<head>
<script type="text/javascript">
var djConfig = {
baseScriptUri : "js/dojo/"
};
</script>
<script type="text/javascript" src="js/dojo/dojo/dojo.js"></script>
<script language="JavaScript" type="text/javascript">
dojo.setObject("person.names.firstName", "A");
alert(dojo.toJson(person));
</script>
</head>
<body></body>
</html>