Lesson 5
The seeIt() function gets called by the onload and onclick event handlers. When they call the function, they pass an event object (which describes the state of an event) as an argument.
seeIt() assigns the value of the event's type attribute to the variable what, and the value of the variable is displayed in an alert box.
event.type tells us the type of event that has occurred - whether it was a load, click, mouseover or any other of the html events that JavaScript can listen for with event handlers.