So, this has been quite a difficult thing to do, so many sources online are either outdated or only address the IE problem and not Firefox.
So here is a very simple, easy & reliable way to make a gif animation continue animating on a pleasewait page. Please note, I use jQuery in this example.
LoadingGIF.html – This is the page in which contains the actual animating gif img, it is a simple html file that is loaded into our PleaseWait.html page using an iframe tag.
<html> <head> <title></title> </head> <body> <img src=”img/ajax-loader.gif” /> </body> </html>
I hope you find this helpful, if you are unsure how to use this example you can just ask me on twitter, I will be glad to help.