How to show a gif while loading all elements of the website?

Dudes, I am looking for a way to show a .gif (loading disc, loading bar or whatever) while all the content (including images of the current page, like backgrounds and illustrations) are being loaded and then, when it all is loaded, show the current page.

I have tried a very simple code that I found here with the .load() event but, apparently, it does not make the function I am looking for.