E4X Alternative - JSOM

I have been expecting the popularity of E4X for a long time. However, as long as Internet Explorer is the most popular browser, "new" standards will never get popular (Microsoft is suffered from Windows XP legacy, too). Instead of waiting for E4X, some developers use XPath to query the DOM nodes while the other traverse the DOM node by node. However, it would be good if we could access XML content in JavaScript Object Model (JSOM):

xml='<invoice date="01-20-2000" number="123">' +
    '  <address country="US">' +
    '    <name>John Smith</name>' +
    '    <street>123 George St.</street>' +
    '    <city>Mountain View</city>' +
    '    <state>CA</state>' +
    '    <zip>94041</zip>' +
    '  </address>' +
    '</invoice>';
invoice = JSOM(xml);
alert(invoice.$number);
alert(invoice.address.name);

There is a project, IEE4X, in SourceForge for the same purpose but it does not work quite well for a few cases. So, I grabbed the idea and implement the JSOM library myself. The code can be download at Shane's Shelf.