Basic operations
Root element
/Element by tag name
//<cars><car></car></cars>
/cars
/cars/carElement by attribute name
//<cars><car make="lexus"></car></cars>
/cars/car[@make="lexus"]///<cars><car></car></cars>
/cars
/cars/car//<cars><car make="lexus"></car></cars>
/cars/car[@make="lexus"]