Please note that the grid and its structure should be created when the event handlers are attached. That is why you cannot attach handlers for the OnXXXCreating and OnXXXCreated events dynamically.
Inside each RadGrid client-side event handler the first argument passed (sender) will point to the grid client object. The second argument (eventArgs) will hold reference properties/objects dependable on the respective client event. They are listed in the separate help topics linked in the next paragraph.
OnGroupCollapsing String, meaningful only when GroupLoadMode="Client"
OnGroupCollapsed String, meaningful only when GroupLoadMode="Client"
OnGroupExpanding String, meaningful only when GroupLoadMode="Client"
OnGroupExpanded String, meaningful only when GroupLoadMode="Client"
OnHierarchyCollapsing String, meaningful only when HierarchyLoadMode="Client"
OnHierarchyCollapsed String, meaningful only when HierarchyLoadMode="Client"
OnHierarchyExpanding String, meaningful only when HierarchyLoadMode="Client"
OnHierarchyExpanded String, meaningful only when HierarchyLoadMode="Client"
When the ClientIDMode property of the RadGrid control is set to Static , all row specific client-side events would not fire.