Undoing pending changes applied to web pages

An efficient approach is provided for handling changes made to the appearance of data in a Data View within a Web page editing program. Instead of immediately modifying the data to reflect each change entered by a user, the changes are accumulated until the user pauses in interacting with the data for a predefined time interval. The one or more changes modify Extensible Stylesheet Language Transformations (XSLT) code that is then employed for producing hypertext markup language (HTML) used in rendering the data within a window of a browser program. The user can cancel the update process, which is carried out in a separate thread, causing the data to be returned to its state before the update began. A user can also select different options that affect the appearance of a preview format used in the Data View.