PDF-XChange Viewer SDK for Developer's
(ActiveX and Simple DLL Versions)
Moderators:PDF-XChange Support, Daniel - PDF-XChange, Chris - PDF-XChange, Sean - PDF-XChange, Vasyl - PDF-XChange, Ivan - Tracker Software, Stefan - PDF-XChange
I'll speak with my colleagues to see why this is causing you troubles but you should be able to obtain the current zoom level using JS.
"this.zoom" should return to you the current zoom level of the currently active document.