With the recent release of Microsoft Windows 8.1, the official release of Internet Explorer version 11 is available for Windows 7.
While this new version provides more performance and HTML 5 compatibility, it currently is not supported by WebEx. This can cause issues with the use of WebEx during our InFlow Technology support sessions. WebEx is planning to have IE 11 supported in late January 2014.
In the mean time, if you have Internet Explorer 11, you can browse to the website link and then go into the Internet Explorer 11 Tools -> Compatibility Mode for viewing and interacting with the WebEx meeting. The other option is to use an alternative browser (Mozilla Firefox/Google Chrome).