Z-index - higher z-index loads first...?

Hi,

I’m aware that an element with a higher z-index value will position itself visually on top of an element with a lower z-index value, however I was wondering…:

When downloading, does a web page load content within an element with higher z-index before it loads content within an element with a lower z-index?

If not, is there any way to tell the browser what part of a web page to load before everything else?

May be a silly sort of question… it sounds like a stretch to me for z-indexes to do this, but I could swear I’ve read it before somewhere.

Was wondering because I have a website with a large-ish background image - around 300kb - and would want the text of the web page to load before the background image.

If not by this method, is doing this possible any other way?