The dot delimits properties and objects. It can find properties of properties of objects too.
The associativity is left to right.
Refer to the Operator Precedence topic for details of execution order.
You can also access the property values as if the object were an array. This:
is equivalent to:
The result will be the value of the property when it is an RValue or a reference to the property when it is an LValue.
ECMA 262 edition 2 - section - 8.6
ECMA 262 edition 2 - section - 11.2
ECMA 262 edition 3 - section - 8.6
ECMA 262 edition 3 - section - 11.2.1