>>What if you could find out the zoom setting, and instead of trying to change the setting, display a good visible information like "Your browser setting is xyz, this webpage is best viewed with this setting etc". That should at least solve that situation you describe above.
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>AFAIK, there is no way to detect that. And yes, as part of the released documentation for the new version, I will have some notes about it. This is not new however. It has been the case for years for all Web sites since modern browsers starting to implement this feature. But, it is good to let the users know about it.

I think with JavaScript is has been done? Have not done it myself though.

http://stackoverflow.com/questions/1713771/how-to-detect-page-zoom-level-in-all-modern-browsers