Namespace

namespace.js

function namespace(str) {
        var L = str.split('.');
        function ns(last, L) {
                if (!L.length) return;
                ns(last[L[0]] = last[L[0]] || {}, L.splice(1))
        }
        ns(window[L[0]] = window[L[0]] || {}, L.splice(1))
}
namespace("x.y.z");
namespace("x.b.c");
x.y.z.foo = 5;
console.log(x.y.z.foo);​​​​​​​​​​​​​​​​​​