Javascript Effect

I have a problem with a certain area of a site where there are some statistics that are taking a long time to populate. Unfortunetly they have to be live so they are pulling large amounts of information from the server and I cannot store it in the database.

I wanted to see if anyone knew of a way where I could have a 'please wait' img show up where the data would normally show up and once the data is done loading/processing the data would be loaded.

I think there is a way to do this in javascript, but maybe some other ways too.