The pdf output start automatically once the window.onload event has finished right?

However in my case due to fusioncharts the html markup in not fully complete by the time the window.onload has finished.

So can i do anything to instruct prince WHEN to start doing the export? some setting to say do not auto export and wait for a command. Say

prince.doOutputNow(); //-- tells prince to do the output now

No, this is not possible. However, in the latest alpha builds Prince will wait until timeouts have run before beginning conversion, which might help.

Thanks will give the alpha a go and let you know.