Implementations Because the DOM supports navigation in any direction (e.g., parent and previous sibling) and allows for arbitrary modifications, implementations typically buffer the document. However, a DOM need not originate in a serialized document at all, but can be created in place with the DOM API. And even before the idea of the DOM originated, there were implementations of equivalent structure with persistent disk representation and rapid access, for example DynaText's model disclosed in and various database approaches.
Implementations Because the DOM supports navigation in any direction (e.g., parent and previous sibling) and allows for arbitrary modifications, implementations typically buffer the document. However, a DOM need not originate in a serialized document at all, but can be created in place with the DOM API. And even before the idea of the DOM originated, there were implementations of equivalent structure with persistent disk representation and rapid access, for example DynaText's model disclosed in and various database approaches.