Event handlers associated with markup language documents represented in a web browser are identified efficiently in response to an event. The markup language document is represented as a hierarchical structure comprising nodes and edges. Nodes are associated with node types, each node type defining how descendants of the node respond to events. The markup language document provides mappings of sets of node types to sets of handlers. In response to an event associated with a node, the types of nodes encountered in a path connecting the node with the root node are identified. Handler sets of the node types encountered in the path connecting a node with the root node are used to determine the handlers to be executed in response to the event. Data is associated with nodes to allow handler code to distinguish between nodes of the same node type.