JS event handler

1, the relationship with the function:

Event: operation elements; all events dependent functions

2, three elements: the event source, event, event handler (function)

3. Event Category:

(1) Event page:

onload: page load event (executed after the page is opened); onunload: Uninstall event page (executed when the page is closed)

(2) mouse events

(3) keyboard events

(4) Other events: more for form