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 |
