[Chameleon] GetJavascriptInitFunctions question

[Yahya]

Hi,
I'm trying to create a custom widget and am having some difficulty figuring 
out how the widgets use javascript. The way I understood it so far is that 
the GetJavascriptxxxxfunctions list the functions to be called for xxxx event 
and GetJavascriptFunctions defines all of these functions. Is this correct?
Also, what is the purpose of GetJavascriptInitFunctions()? How is it different 
from GetJavascriptOnloadfunctions()? Aren't the js functions listed in both 
of these  executed just after the page loads?

Thanks,
Yahya Mohammad