Edit-time redirect for HTML documents

Redirecting an editing environment to open a primary file instead of an associated supporting file. Each supporting file can be provided with a marker identifying it as a supporting file and specifying the location of the primary file associated with that supporting file. This can be done in response to the initiation of a file save event for saving the supporting file. For opening a file in the editing environment, the file open process relies on the presence of a marker in the file to determine if the file is a supporting file. If so, the editing environment is redirected to open the primary file with which the supporting file is associated. For example, for an HTML document containing a primary file and a supporting file, the editing environment is directed to open the primary file rather than the supporting file to support the presentation of the entire content of the HTML document for editing by the user.