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# event

The `event` object contains properties that describe a JavaScript event, and is passed as an argument to an event handler when the event occurs.

Client-side object |
Implemented in | JavaScript 1.2

In the case of a mouse-down event, for example, the `event` object contains the type of event (in this case MouseDown), the x and y position of the cursor at the time of the event, a number representing the mouse button used, and a field containing the modifier keys (Control, Alt, Meta, or Shift) that were depressed at the time of the event. The properties used within the `event` object vary from one type of event to another. This variation is provided in the descriptions of individual event handlers. See Chapter 3, "Event Handlers," for complete information about event handlers. For more information on handling events, see the Client-Side JavaScript Guide.

#### Created by

`event` objects are created by Communicator when an event occurs. You do not create them yourself.

#### Security

Setting any property of this object requires the `UniversalBrowserWrite` privilege. In addition, getting the `data` property of the `DragDrop` event requires the `UniversalBrowserRead` privilege. For information on security, see the Client-Side JavaScript Guide.

#### Property Summary

Not all of these properties are relevant to each event type. To learn which properties are used by an event, see the "Event object properties used" section of the individual event handler.

Property | Description
--- | ---
    data
| Returns an array of strings containing the URLs of the dropped objects. Passed with the DragDrop event.
    height
| Represents the height of the window or frame.
    layerX
| Number specifying either the object width when passed with the resize event, or the cursor's horizontal position in pixels relative to the layer in which the event occurred. Note that `layerX` is synonymous with x.
    layerY
| Number specifying either the object height when passed with the resize event, or the cursor's vertical position in pixels relative to the layer in which the event occurred. Note that `layerY` is synonymous with y.
    modifiers
| String specifying the modifier keys associated with a mouse or key event. Modifier key values are: ALT_MASK, CONTROL_MASK, SHIFT_MASK, and META_MASK.
    pageX
| Number specifying the cursor's horizontal position in pixels, relative to the page.
    pageY
| Number specifying the cursor's vertical position in pixels relative to the page.
    screenX
| Number specifying the cursor's horizontal position in pixels, relative to the screen.
    screenY
| Number specifying the cursor's vertical position in pixels, relative to the screen.
    target
| String representing the object to which the event was originally sent. (All events)
    type
| String representing the event type. (All events)
    which
| Number specifying either the mouse button that was pressed or the ASCII value of a pressed key. For a mouse, 1 is the left button, 2 is the middle button, and 3 is the right button.
    width
| Represents the width of the window or frame.
    x
| Synonym for `layerX`.
    y
| Synonym for `layerY`.

#### Method Summary

This object inherits the `watch` and `unwatch` methods from `Object`.

#### Examples

The following example uses the event object to provide the type of event to the alert message.

    <A HREF="http://home.netscape.com" onClick='alert("Link got an event: "
    + event.type)'>Click for link event</A>

The following example uses the event object in an explicitly called event handler.

    <SCRIPT>
    function fun1(evnt) {
       alert ("Document got an event: " + evnt.type);
       alert ("x position is " + evnt.layerX);
       alert ("y position is " + evnt.layerY);
       if (evnt.modifiers & Event.ALT_MASK)
          alert ("Alt key was down for event.");
       return true;
       }
    document.onmousedown = fun1;
    </SCRIPT>

## data

For the DragDrop event, returns an array of strings containing the URLs of the dropped objects.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. In addition, getting this property for the `DragDrop` event requires the `UniversalBrowserRead` privilege. For information on security, see the Client-Side JavaScript Guide.

## height

Represents the height of the window or frame.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.width`

## layerX

Number specifying either the object width when passed with the resize event, or the cursor's horizontal position in pixels relative to the layer in which the event occurred.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### Description

This property is synonymous with the `event.x` property.

#### See also

`event.layerY`

## layerY

Number specifying either the object height when passed with the resize event, or the cursor's vertical position in pixels relative to the layer in which the event occurred.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### Description

This property is synonymous with the `event.y` property.

#### See also

`event.layerX`

## modifiers

String specifying the modifier keys associated with a mouse or key event. Modifier key values are: ALT_MASK, CONTROL_MASK, SHIFT_MASK, and META_MASK.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.which`

## pageX

Number specifying the cursor's horizontal position in pixels, relative to the page.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.pageY`

## pageY

Number specifying the cursor's vertical position in pixels relative to the page.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.pageX`

## screenX

Number specifying the cursor's horizontal position in pixels, relative to the screen.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.screenY`

## screenY

Number specifying the cursor's vertical position in pixels, relative to the screen.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.screenX`

## target

String representing the object to which the event was originally sent.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.type`

## type

String representing the event type.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.target`

## which

Number specifying either the mouse button that was pressed or the ASCII value of a pressed key. For a mouse, 1 is the left button, 2 is the middle button, and 3 is the right button.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.modifiers`

## width

Represents the width of the window or frame.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### See also

`event.height`

## x

Number specifying either the object width when passed with the resize event, or the cursor's horizontal position in pixels relative to the layer in which the event occurred.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### Description

This property is synonymous with the `event.layerX` property.

#### See also

`event.y`

## y

Synonym for `layerY`.

Property of | `event`
Implemented in | JavaScript 1.2

#### Security

Setting this property requires the `UniversalBrowserWrite` privilege. For information on security, see the Client-Side JavaScript Guide.

#### Description

This property is synonymous with the `event.layerY` property.

#### See also

`event.x`

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Last Updated: 05/28/99 11:59:24

Copyright (c) 1999 Netscape Communications Corporation