I'm not sure your solution will work, dhaywirex.
I came up with this (I'm not sure this will work, either....):
var loadingWin = window.open('about
loadingWin.document.write('<html><head><title>Load ing...</title></head><body>Please wait. The page you requested is loading.</body></html>');
'do your queries here
This script should (no guarantees here) pop up a window as soon as it's opened, and then close it when it's done loading.
Let me know if it works.