//The client side event SplitterBarMouseUp takes two parameters, sender and e.
//Sender is the object which is raising the event
//e is the EventArgs
function WebSplitter1_SplitterBarMouseUp(sender, e) {
var websplitter = $find("WebSplitter1");
// Gets reference to pane at index 0;
websplitterPane = websplitter.getPaneAt(0);
// Gets reference to pane at index 1
websplitterPane1 = websplitter.getPaneAt(1);
// Collapse pane 0
websplitterPane.set_collapsed(true);
// Collapse pane 1
websplitterPane1.set_collapsed(true);
//Gets refernce to the browser event
var browserRef = e.get_browserEvent();
}