xml dom - create element with namespace (cross browser)

var xmlDoc;
////some code to load and initialize xmlDoc..

//create an element 'book', with prefix 'px' and namespace 'http://bookshop.com/schema'
var bookelement;

if (xmlDoc.createElementNS) { //for other browsers than ie
    bookelement = xmlDoc.createElementNS('px:book', 'http://bookshop.com/schema');
}
else { //for ie
    bookelement = xmlDoc.createNode(1, 'px:book', 'http://bookshop.com/schema');
}

will create book element:

<px:book xmlns:px='http://bookshop.com/schema' />