use this function to create a namespace

namespace.js

function namespace(namespaceString) {
    var parts = namespaceString.split('.'),
        parent = window,
        currentPart = '';    
        
    for(var i = 0, length = parts.length; i < length; i++) {
        currentPart = parts[i];
        parent[currentPart] = parent[currentPart] || {};
        parent = parent[currentPart];
    }
    
    return parent;
}

var bar = namespace('foo.bar'); // {}
bar.test=true;
console.log(foo.bar); // {test:true}