Hi everybody, I need to code a webpart which purpose is to asynchronously fetch some documents and display them into an existing page. Unfortunately I have to face a lot of rescritcions and my struggle to find a solution seems useleess so far.

1) I cannot use Microsoft asp.net ajax
2) I must use Jsonp because the called service (page, whatever...) is outside the site's domain. That's not a big problem.
3) I have no possibility to alter the existing page code, so I cannot reference an external library such as JQuery.
4) For the same reason I have no possibility to call my methods on the window.onLoad event, so here the question is: how can I be sure that everything is correctly loaded before triggering my ajax call?
5) Since several instances of the same webpart can be placed into the same page, can there be some possible conflicts among the various js functions?