Embodiments are directed to computing, by an apparatus comprising a processing device, an identifier (ID) for an element in a page using an algorithm responsive to encountering the element a first time, causing, by the apparatus, the ID to be stored in a storage device, encountering, by the apparatus, the element a second time, determining, by the apparatus, that the element is encountered the second time, and responsive to determining that the element is encountered the second time, representing, by the apparatus, the element by the ID at the time of the second encounter by retrieving the ID from the storage device.