Is there a way to open a web application from Qv using a macro? If so, can I also use parameteres to control the window size, with/without toolbars, etc.?
If using V9, use the External->Open URL action. For V8, the macro call is ActiveDocument.GetApplication.Launch.
Parameters to control window size etc are going to be whatever is recognized by your web app and server. It's not a function of the Launch. If you want to open without toolbars you may need to create an entry page on your web app that does the window open without toolbars.
