We are hosting some SP2010 sites and some of our users are a little quick on the trigger and try to click on an order before the page is done loading, inadvertantly approving it by mistake. Repeated attempts to scold them have failed and so I would like to find out if there is an approved or correct way to insitutue something like a full screen pre-loader, something like a blockUI? In ASP.NET for example, you can just hook to the AJAX toolkit, and I'm sure there is something similar in SharePoint, but if there is a cleaner way, I would like to know about it.
ADD: What I would like to do is catch the event. So in ASP.NET you could do something like this:
var pmgr = Sys.WebForms.PageRequestManager.getInstance();
pmgr.add_beginRequest(foo());
... and than you could catch the event. I'm trying to accomplish the same thing but in SharePoint.