Well, GoDiagram Web doesn't define a separate document object on the client, not to be confused with the document object in the HTML DOM.
The transmission of properties for GoObjects is achieved through GoPartInfos and GoViewDataRenderer. This is described in GoWebIntro.doc. But there isn't a GoPartInfo defined for the view's GoDocument.
Then you could refer to it by:
var v = goFindView('MyView');
... v.MyProperty ...