HTML DOM Event Object(转)

HTML DOM Event Object

Event Object

The event object gives you information about an event that has occurred.

The Event object represents the state of an event, such as the element in which the event occurred, the state of the keyboard keys, the location of the mouse, and the state of the mouse buttons.

Events are normally used in combination with functions, and the function will not be executed before the event occurs!

Event Handlers

New to HTML 4.0 was the ability to let HTML events trigger actions in the browser, like starting a JavaScript when a user clicks on an HTML element. Below is a list of the attributes that can be inserted into HTML tags to define event actions.

IE: Internet Explorer, F: Firefox, O: Opera, W3C: W3C Standard.

Attribute	The event occurs when...	IE	F	O	W3C
onblur	An element loses focus	3	1	9	Yes
onchange	The content of a field changes	3	1	9	Yes
onclick	Mouse clicks an object	3	1	9	Yes
ondblclick	Mouse double-clicks an object	4	1	9	Yes
onerror	An error occurs when loading a document or an image	4	1	9	Yes
onfocus	An element gets focus	3	1	9	Yes
onkeydown	A keyboard key is pressed	3	1	No	Yes
onkeypress	A keyboard key is pressed or held down	3	1	9	Yes
onkeyup	A keyboard key is released	3	1	9	Yes
onmousedown	A mouse button is pressed	4	1	9	Yes
onmousemove	The mouse is moved	3	1	9	Yes
onmouseout	The mouse is moved off an element	4	1	9	Yes
onmouseover	The mouse is moved over an element	3	1	9	Yes
onmouseup	A mouse button is released	4	1	9	Yes
onresize	A window or frame is resized	4	1	9	Yes
onselect	Text is selected	3	1	9	Yes
onunload	The user exits the page	3	1	9	Yes

Mouse / Keyboard Attributes

Property	Description	IE	F	O	W3C
altKey	Returns whether or not the "ALT" key was pressed when an event was triggered	6	1	9	Yes
button	Returns which mouse button was clicked when an event was triggered	6	1	9	Yes
clientX	Returns the horizontal coordinate of the mouse pointer when an event was triggered	6	1	9	Yes
clientY	Returns the vertical coordinate of the mouse pointer when an event was triggered	6	1	9	Yes
ctrlKey	Returns whether or not the "CTRL" key was pressed when an event was triggered	6	1	9	Yes
metaKey	Returns whether or not the "meta" key was pressed when an event was triggered	6	1	9	Yes
relatedTarget	Returns the element related to the element that triggered the event	No	1	9	Yes
screenX	Returns the horizontal coordinate of the mouse pointer when an event was triggered	6	1	9	Yes
screenY	Returns the vertical coordinate of the mouse pointer when an event was triggered	6	1	9	Yes
shiftKey	Returns whether or not the "SHIFT" key was pressed when an event was triggered	6	1	9	Yes

Other Event Attributes

Property	Description	IE	F	O	W3C
bubbles	Returns a Boolean value that indicates whether or not an event is a bubbling event	No	1	9	Yes
cancelable	Returns a Boolean value that indicates whether or not an event can have its default action prevented	No	1	9	Yes
currentTarget	Returns the element whose event listeners triggered the event	No	1	9	Yes
eventPhase	Returns which phase of the event flow is currently being evaluated				Yes
target	Returns the element that triggered the event	No	1	9	Yes
timeStamp	Returns the time stamp, in milliseconds, from the epoch (system start or event trigger)	No	1	9	Yes
type	Returns the name of the event	6	1	9	Yes