Some People Should Not be Allowed to Own Computers

I was asked to update a website for a local private school. I've been emailing back and forth with the principal about the needed changes. This afternoon I posted what I have done so far and her reply was when she looked there was no changes. I wrote back instructions about how some web browsers save a copy of web pages and so when you visit it again it just loads the old version it has saved. I gave her instructions on how to clear the cache so she could view the changes I made. Her reply: the content had not been updated. ARgh. Grumble, grumble.