Animation editing

An animation can be selected. Pieces of the documents that pertain to the selected animation can be extracted from the document closure for the web page in which the animation appears. A composite data structure can be created therefrom. The winning set of @keyframes rules referenced by the animation-name property of a style rule (the virtual winning rule) can be computed and represented in a data structure. The winning animation properties can establish the timing properties to preview and edit the animation in a user interface without running the whole application. The data structure represented in the visual preview can be edited by applying user gestures to the animation displayed in a preview user interface (UI). The user changes can be mapped to changes to property values in the data structure and the underlying documents.