In all the quizzes which use a pop-up Periodic Table, under IE4 a JavaScript error is issued if you close the window for the quiz from which the Periodic Table was called and then attempt to return to the quiz using the button on the Periodic Table page called 'Hide Periodic Table and Return to Quiz'. This occurs because the window.opener property appears to be destroyed when the opening window is closed.
The problem does not occur with Netscape Navigator which correctly sets the window.opener.closed property to true if the window from which the Periodic Table was opened is subsequently closed.
Problems may be experienced when running the enthalpy definition quizzes on a network.
The cause of this is highly technical and I'm not sure I fully understand it myself.
All these quizzes use frames which communicate with one another using JavaScript. Depending on how your network is set up, one of the inbuilt security features of JavaScript may incorrectly be invoked. This feature is designed to prevent JavaScript from one server being run on another server.
There are two ways around this problem.
Avoid accessing the quiz via a hyperlink, instead (i) open the quiz using the standard File-Open command or (ii) by dragging and dropping the file on to the icon for Netscape Navigator or Internet Explorer.