Safe deep property access in JavaScript

sprop.js

// Gets the deep value of property specified in the ns param.
// Will always return undefined any properties don't exist or if obj input is invalid.
// obj (object): The object to inspect.
// ns (array of strings): Ordered properties that are the namespace to the property of interest.
// returns: Whatever value the property contains, or undefined

function sprop(obj, ns) {

	var result, i, len;

	if (!obj) {
		return;
	}

	result = obj;
	i = 0;
	len = props.length;

	for(; i<len; i++) {
		if (typeof(result) === 'object' && props[i] in result) {
			result = result[props[i]];
		}
		else {
			return;
		}
	}

	return result;
	}
}