body onload won't fire due to video stream

[NewtownGuy]

BODY onload="initScript();" won't execute my initScript, apparently because my page immediately loads a live M-JPEG video stream and thus the page never finishes loading all of the images. I've tried invoking initScript at the bottom of my JS functions, but sometimes it fires before the page finishes loading. I've tried invoking initScript from JS code at the very bottom of my page, but sometimes it doesn't fire.

I know the page is otherwise ok because it works right if I include a button that I have to click to run initScript.

How can I solve this problem ?

Thank you in advance for your help.