I had to look this one up. Paraphrased/quoted from my old "dummies" book.
Use the refresh method of the navigator.plugins array to load and make available any newly installed plugins. (Normally users have to close and reopen their browsers to refresh newly installed plugins.
The reload method of the location object forces reload of the document specified by the URL in the href property of the location object. The result of the reload method is the same as clicking the reload button in NS or the refresh button in IE