Interaction History Support for Web Applications

All users of complex software make decisions that they may later wish to change. Many computer systems have tools to support this need for revision, such as the undo command. However, the common history tools (like undo) do not support exploratory, epistemic interaction well. And there are common, non-specialized tasks that are difficult in common computer systems, but would be much easier with improved support for managing interaction history. Desktop computing environments have well-established norms for how undo works, but there is room to explore this in newer computing environments, such as the Web and surface computing, as their design culture has not stabilized to the same extent. We argue that history tracking needs to be more accessible to users.We developed a prototype JavaScript library for Web applications that lets users keep a history of all their interaction states, including those that would be discarded by using a traditional stack-model undo system. The history is presented to users in a tree structure similar to the model used in source control software. We ran a usability study of our system with two applications designed to encourage the kind of exploratory behaviour we wanted to support. We identified usability improvements that could be made, but the study suggests that this kind of system could be generally useful even in non-specialized fields.