IZoomEvents interface

Provides a method that notifies hosts of changes in the zoom state.


The IZoomEvents interface inherits from the IUnknown interface but does not have additional members.


IZoomEvents was introduced in Windows Internet Explorer 7.

To be notified of changes in the zoom level of a Web page, hosts of MSHTML should implement this interface on the same object that implements IOleClientSite. The WebBrowser control does not delegate IZoomEvents to its host.

Note  The optical zoom keyboard shortcuts (CTRL+mouse wheel forward/back, CTRL+PLUS SIGN, and CTRL+MINUS SIGN) are not enabled by default when hosting the WebBrowser control. To enable this behavior, call IWebBrowser2::ExecWB with OLECMDID_OPTICAL_ZOOM, passing 100 in pvaIn. Once set, the keyboard shortcuts remain available as long as the host navigates to HTML content because the same instance of MSHTML is used. However, if the host navigates to Active documents, such as XML or Portable Document Format (PDF) files, optical zoom is disabled and will need to be enabled again.


Minimum supported client

Windows Vista

Minimum supported server

Windows Server 2008