A JavaScript function to create namespaces, avoiding the global namespace and keeping any existing or already defined namespaces intact..

createNamespace.js

function createNamespace(namespaceString, scope)
{
	// eg: 'company.section.product.model.version' => ['company', 'section', 'product', 'model', 'version']
	var nsNames = namespaceString.split(/[:\.]/g),
	
		// store this to save looking it up on every pass of the loop
	    nsNamesLength = nsNames.length,
	    
	    // an optional object to apply the namespace to, eg: myObj.company.* if set, otherwise window.company.*
	    refs = [scope || window],
	    
	    // the current object having a new namespace property added to it
	    nsParent,
	    
	    // the current property/namespace being added to the current object
	    namespace,
	    
	    // loop iterator
	    i;

	if (nsNamesLength)
	{
		for (i = 0; i < nsNamesLength; i++)
		{
			// get the next namespace/property from the array
			namespace = nsNames[i];
			
			// get the current object having a new namespace property added to it
			nsParent = refs[i];
			
			// if nothing exists at this namespace already
			if (typeof nsParent[namespace] === 'undefined')
			{
				// create it
				nsParent[namespace] = {};
			}
			
			// move along the namespace chain to add the next level down onto it
			refs.push(nsParent[namespace]);
		}
	}
}

var someObject = {}; 
createNamespace('company.section.product.model.version', someObject);

will output

{
    company: {
        section: {
            product: {
                model: {
                    version: {}
                }
            }
        }
    }
};