Description 
Use the OnClick event handler to write code that responds to the click event. Because the buttons on the navigator already have default actions that occur when they are clicked, it isn't necessary to write an OnClick event handler.
 
The OnClick event occurs when
 
The user clicks one the buttons on the navigator with the mouse
 
The user presses Spacebar while the navigator has focus.
 
The BtnClick method is called.
 
Note: The OnClick event occurs after the default action for the clicked button. 

