RowSelectionChanging Property

// The client event RowSelectionChanging takes two parameters sender and e
// sender  is the object which is raising the event
// e is the RowSelectionChangingEventArgs

function WDG1_RowSelectionChanging(sender, e) {

    //Returns a Read Only collection of the currently selected rows
    var currentSelectedRows = e.getCurrentSelectedRows();

    //Returns the number of rows in the collection
    var currentLength = currentSelectedRows.get_length();

    //Returns a Read Only collection of the newly selected rows
    var newSelectedRows = e.getNewSelectedRows();

    var newLength = newSelectedRows.get_length();

    window.status = "The number of rows selected changed from '" + currentLength + "' to '" + newLength + "'";
        
}