DOM event

DOM Events are a signal that something has occurred, or is occurring, and can be triggered by user interactions or by the browser. Client-side scripting languages like JavaScript, JScript, VBScript, and Java can register various event handlers or listeners on the element nodes inside a DOM tree, such as in HTML, XHTML, XUL, and SVG documents.
Examples of DOM Events:

When a user clicks the mouse
When a web page has loaded
When an image has been loaded
When the mouse moves over an element
When an input field is changed
When an HTML form is submitted
When a user presses a key

Historically, like DOM, the event models used by various web browsers had some significant differences which caused compatibility problems. To combat this, the event model was standardized by the World Wide Web Consortium in DOM Level 2.

Events

HTML events

Common events

There is a huge collection of events that can be generated by most element nodes:

Mouse events.
Keyboard events.
HTML frame/object events.
HTML form events.
User interface events.
Mutation events.
Progress events.

Note that the event classification above is not exactly the same as W3C's classification.

Category	Type	Attribute	Description	Bubbles	Cancelable
Mouse	click	onclick	Fires when the pointing device button is clicked over an element. A click is defined as a mousedown and mouseup over the same screen location. The sequence of these events is: mousedown mouseup click
Mouse	dblclick	ondblclick	Fires when the pointing device button is double-clicked over an element
Mouse	mousedown	onmousedown	Fires when the pointing device button is pressed over an element
Mouse	mouseup	onmouseup	Fires when the pointing device button is released over an element
Mouse	mouseover	onmouseover	Fires when the pointing device is moved onto an element
Mouse	mousemove	onmousemove	Fires when the pointing device is moved while it is over an element
Mouse	mouseout	onmouseout	Fires when the pointing device is moved away from an element
Mouse	dragstart	ondragstart	Fired on an element when a drag is started.
Mouse	drag	ondrag	This event is fired at the source of the drag, that is, the element where dragstart was fired, during the drag operation.
Mouse	dragenter	ondragenter	Fired when the mouse is first moved over an element while a drag is occurring.
Mouse	dragleave	ondragleave	This event is fired when the mouse leaves an element while a drag is occurring.
Mouse	dragover	ondragover	This event is fired as the mouse is moved over an element when a drag is occurring.
Mouse	drop	ondrop	The drop event is fired on the element where the drop occurs at the end of the drag operation.
Mouse	dragend	ondragend	The source of the drag will receive a dragend event when the drag operation is complete, whether it was successful or not.
Keyboard	keydown	onkeydown	Fires before keypress, when a key on the keyboard is pressed.
Keyboard	keypress	onkeypress	Fires after keydown, when a key on the keyboard is pressed.
Keyboard	keyup	onkeyup	Fires when a key on the keyboard is released
HTML frame/object	load	onload	Fires when the user agent finishes loading all content within a document, including window, frames, objects and imagesFor elements, it fires when the target element and all of its content has finished loading
HTML frame/object	unload	onunload	Fires when the user agent removes all content from a window or frame For elements, it fires when the target element or any of its content has been removed
HTML frame/object	abort	onabort	Fires when an object/image is stopped from loading before completely loaded
HTML frame/object	error	onerror	Fires when an object/image/frame cannot be loaded properly
HTML frame/object	resize	onresize	Fires when a document view is resized
HTML frame/object	scroll	onscroll	Fires when an element or document view is scrolled	, except that a scroll event on document must bubble to the window
HTML form	select	onselect	Fires when a user selects some text in a text field, including input and textarea
HTML form	change	onchange	Fires when a control loses the input focus and its value has been modified since gaining focus
HTML form	submit	onsubmit	Fires when a form is submitted
HTML form	reset	onreset	Fires when a form is reset
HTML form	focus	onfocus	Fires when an element receives focus either via the pointing device or by tab navigation
HTML form	blur	onblur	Fires when an element loses focus either via the pointing device or by tabbing navigation
User interface	focusin		Similar to HTML focus event, but can be applied to any focusable element
User interface	focusout		Similar to HTML blur event, but can be applied to any focusable element
User interface	DOMActivate		Similar to XUL command event. Fires when an element is activated, for instance, through a mouse click or a keypress.
Mutation	DOMSubtreeModified		Fires when the subtree is modified
Mutation	DOMNodeInserted		Fires when a node has been added as a child of another node
Mutation	DOMNodeRemoved		Fires when a node has been removed from a DOM-tree
Mutation	DOMNodeRemovedFromDocument		Fires when a node is being removed from a document
Mutation	DOMNodeInsertedIntoDocument		Fires when a node is being inserted into a document
Mutation	DOMAttrModified		Fires when an attribute has been modified
Mutation	DOMCharacterDataModified		Fires when the character data has been modified
Progress	loadstart		Progress has begun.
Progress	progress		In progress. After loadstart has been dispatched.
Progress	error		Progression failed. After the last progress has been dispatched, or after loadstart has been dispatched if progress has not been dispatched.
Progress	abort		Progression is terminated. After the last progress has been dispatched, or after loadstart has been dispatched if progress has not been dispatched.
Progress	load		Progression is successful. After the last progress has been dispatched, or after loadstart has been dispatched if progress has not been dispatched.
Progress	loadend		Progress has stopped. After one of error, abort, or load has been dispatched.

Note that the events whose names start with "DOM" are currently not well supported, and for this and other performance reasons are deprecated by the W3C in DOM Level 3. Mozilla and Opera support DOMAttrModified, DOMNodeInserted, DOMNodeRemoved and DOMCharacterDataModified. Chrome and Safari support these events, except for DOMAttrModified.

Touch events

Web browsers running on touch-enabled devices, such as Apple's iOS and Google's Android, generate additional events.

Category	Type	Attribute	Description	Bubbles	Cancelable
Touch	touchstart		Fires when a finger is placed on the touch surface/screen.
Touch	touchend		Fires when a finger is removed from the touch surface/screen.
Touch	touchmove		Fires when a finger already placed on the screen is moved across the screen.
Touch	touchenter		Fires when a touch point moves onto the interactive area defined by a DOM element.
Touch	touchleave		Fires when a touch point moves off the interactive area defined by a DOM element.
Touch	touchcancel		A user agent must dispatch this event type to indicate when a TouchPoint has been disrupted in an implementation-specific manner, such as by moving outside the bounds of the UA window. A user agent may also dispatch this event type when the user places more touch points on the touch surface than the device or implementation is configured to store, in which case the earliest TouchPoint object in the TouchList should be removed.

In the W3C draft recommendation, a TouchEvent delivers a TouchList of Touch locations, the modifier keys that were active, a TouchList of Touch locations within the targeted DOM element, and a TouchList of Touch locations that have changed since the previous TouchEvent.
Apple didn't join this working group, and delayed W3C recommendation of its Touch Events Specification by disclosing patents late in the recommendation process.