A method for processing a Document Object Model (DOM) tree to verify context between multiple related XML tags. One or more of these related XML tags are custom tags. According to the invention, contextual relationships between the related XML tags are verified using the DOM itself to indicate state. In a preferred embodiment, the inventive method begins during the processing of the DOM tree with a current element being processed replacing itself with a placeholder element. The placeholder element includes attributes indicating its state. If a clean-up element does not already exist for the element being processed, the current element creates a clean-up element and adds it to the DOM, for example, as a child node to the root position. When the clean-up element is later encountered, this element scans the entire DOM for all the related tags (now placeholders) of interest. The clean-up element loads the state information from each and processes the state information accordingly. When complete, the clean-up element removes itself from the DOM.