How do you execute a Javascript function when the page has fully rendered?

Question

How would you go about executing a Javascript function when the page is fully rendered (Displayed) I know that the onLoad event executes when the page is loaded but Before i

Answer 1

The onload event fires when the page is fully rendered (including dependancies such as images).

Perhaps you are confusing it with Prototype's dom:loaded event (which fires when the DOM is loaded but before all the dependancies have been included)?

(To be honest, this sounds like an X-Y problem.)