general before/after JavaScript mechanism

"Lunching with JavaScript returns:
http://groups.google.com/group/liftweb/browse_thread/thread/b3469ab5eb55c7f5/32a6b3f8f482a8b7

I think we need a general before/after JavaScript mechanism... and I have an idea of how it can be done with only 2 API calls:

SHtml.beforeAjax(jsCmd) {
SHtml.afterAjax(jsCmd) {
code that creates an AjaxCall
}
}

Those two calls will wrap the pre and post execution of the Ajax call and will work across all the Ajax call mechanisms. Further, they answer the need for an "in call" spinny control located near the item that's doing the Ajax call rather than the global spinny thing for Ajax calls."

See related thread
http://groups.google.com/group/liftweb/browse_thread/thread/c0fa111d87a8beac