html - When does a body onLoad gets called?

Question

I need to understand when does a body's onload gets called

I read in w3school that onload=Script to be run when a document load what does this mean?

Does it mean that

1. the html/jsp page gets loaded before rendering any elements in the body like any table or jsp scriplets eg: <%= request.getParameter("NAME") %>
2. Or is it after the page/body is rendered?

for example: I have a bunch of params (<%= request.getParameter("NAME") %>,...) so in order to use them i'll place them in some hidden form item & then on body load can I use them?

Answer 1

Unlike w3schools, MDN explains when the event is fired:

The load event fires at the end of the document loading process. At this point, all of the objects in the document are in the DOM, and all the images and sub-frames have finished loading.

So the DOM tree is ready and all elements have been loaded.