Ugly JXON for Custom Buttons

jxon.js

var xul = {
	$tagName: "menupopup",
	$xmlns: "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul",
	$property: { toString: function() { return "[Object RawProperty]"; } },
	$oncommand: function(e) {
		alert(e.target.getAttribute("value"));
	},
	oncommand: "this.oncommand(event);",
	$childNodes: [
		{ $tagName: "menuitem", label: "Item - 0", value: "0" },
		{ $tagName: "menuitem", label: "Item - 1", value: "1" }
	]
};
var o = {
	parseFromObject: function(o) {
		if("$textContent" in o)
			return document.createTextNode(o.$textContent);
		var node = document.createElementNS(
			o.$xmlns || "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul",
			o.$tagName
		);
		for(var p in o) if(o.hasOwnProperty(p)) {
			if(p == "$childNodes") { // Child nodes
				o[p].forEach(function(child) {
					node.appendChild(this.parseFromObject(child));
				}, this);
				continue;
			}
			if(p.charAt(0) == "$") { // Properties
				if(p != "$tagName" && p != "$xmlns")
					node[p.substr(1)] = o[p];
				continue;
			}
			// Attributes
			var attr = o[p];
			if(typeof attr == "object")
				node.setAttributeNS(attr.$xmlns, p, attr.value);
			else
				node.setAttribute(p, attr);
		}
		return node;
	}
};
var menu = o.parseFromObject(xul);
document.documentElement.appendChild(menu);
//alert(new XMLSerializer().serializeToString(menu));
alert(menu.property);
menu.showPopup();
setTimeout(function() {
	menu.parentNode.removeChild(menu);
}, 1e4);