| Client-side object | |
| Implemented in | Navigator 4.0 |
Created by
The HTML LAYER or ILAYER tag, or using cascading style sheet syntax. The JavaScript runtime engine creates a Layer object corresponding to each layer in your document. It puts these objects in an array in the document.layers property. You access a Layer object by indexing this array.
To define a layer, use standard HTML syntax. If you specify the ID attribute, you can use the value of that attribute to index into the layers array.
For a complete description of layers, see Dynamic HTML in Netscape Communicator1.
Some layer properties can be directly modified by assignment; for example,
"mylayer.visibility = hide". A layer object also has methods that can
affect these properties.
Event handlers
Note
Just as in the case of a document, if you want to define mouse click response for a layer, you must capture onMouseDown and onMouseUp events at the level of the layer and process them as you want.
See "Events in Navigator 4.0" for more details about capturing events.
If an event occurs in a point where multiple layers overlap, the topmost layer gets the event, even if it is transparent. However, if a layer is hidden, it does not get events.
Properties
above
The layer object above this one in z-order, among all layers in the document or the enclosing window object if this layer is topmost.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
background
The image to use as the background for the layer's canvas (which is the part of the layer within the clip rectangle).
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
Description
Each layer has a background property, whose value is an image object, whose src attribute is a URL that indicates the image to use to provide a tiled backdrop. The value is null if the layer has no backdrop. For example:
layer.background.src = "fishbg.gif";
bgColor
A string specifying the color to use as a solid background color for the layer's canvas (the part of the layer within the clip rectangle).
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
Description
The bgColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in the JavaScript Guide. This property is the JavaScript reflection of the BGCOLOR attribute of the BODY tag.
You can set the bgColor property at any time.
If you express the color as a hexadecimal RGB triplet, you must use the format rrggbb. For example, the hexadecimal RGB values for salmon are red=FA, green=80, and blue=72, so the RGB triplet for salmon is "FA8072".
Examples
The following example sets the background color of the myLayer layer's canvas to aqua using a string literal:
myLayer.bgColor="aqua"
The following example sets the background color of the myLayer layer's canvas to aqua using a hexadecimal triplet:
myLayer.bgColor="00FFFF"
See also
Layer.bgColor
below
The layer object below this one in z-order, among all layers in the document or null if this layer is at the bottom.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
clip.bottom
The bottom edge of the clipping rectangle (the part of the layer that is visible.) Any part of a layer that is outside the clipping rectangle is not displayed.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
clip.height
The height of the clipping rectangle (the part of the layer that is visible.) Any part of a layer that is outside the clipping rectangle is not displayed.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
clip.left
The left edge of the clipping rectangle (the part of the layer that is visible.) Any part of a layer that is outside the clipping rectangle is not displayed.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
clip.right
The right edge of the clipping rectangle (the part of the layer that is visible.) Any part of a layer that is outside the clipping rectangle is not displayed.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
clip.top
The top edge of the clipping rectangle (the part of the layer that is visible.) Any part of a layer that is outside the clipping rectangle is not displayed.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
clip.width
The width of the clipping rectangle (the part of the layer that is visible.) Any part of a layer that is outside the clipping rectangle is not displayed.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
document
The layer's associated document.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
Description
Each layer object contains its own document object. This object can be used to access the images, applets, embeds, links, anchors and layers that are contained within the layer. Methods of the document object can also be invoked to change the contents of the layer.
left
The horizontal position of the layer's left edge, in pixels, relative to the origin of its parent layer.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
name
A string specifying the name assigned to the layer through the ID attribute in the LAYER tag.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
pageX
The horizontal position of the layer, in pixels, relative to the page.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
pageY
The vertical position of the layer, in pixels, relative to the page.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
parentLayer
The layer object that contains this layer, or the enclosing window object if this layer is not nested in another layer.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
siblingAbove
The layer object above this one in z-order, among all layers that share the same parent layer or null if the layer has no sibling above.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
siblingBelow
The layer object below this one in z-order, among all layers that share the same parent layer or null if layer is at the bottom.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
src
A URL string specifying the source of the layer's content. Corresponds to the SRC attribute.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
top
The top property is a synonym for the topmost Navigator window, which is a document window or web browser window.
| Property of |
Layer
|
| Read-only | |
| Implemented in | Navigator 4.0 |
Description
The top property refers to the topmost window that contains frames or nested framesets. Use the top property to refer to this ancestor window.
The value of the top property is
<object
where objectReference>objectReference is an internal reference.
Examples
The statement top.close() closes the topmost ancestor window.
The statement top.length specifies the number of frames contained within the topmost ancestor window. When the topmost ancestor is defined as follows, top.length returns three:
<FRAMESET COLS="30%,40%,30%">
<FRAME SRC=child1.htm NAME="childFrame1">
<FRAME SRC=child2.htm NAME="childFrame2">
<FRAME SRC=child3.htm NAME="childFrame3">
</FRAMESET>visibility
Whether or not the layer is visible.
| Property of |
Layer
|
| Implemented in | Navigator 4.0 |
Description
A value of show means show the layer; hide means hide the layer; inherit means inherit the visibility of the parent layer.
zIndex
The relative z-order of this layer with respect to its siblings.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Description
Sibling layers with lower numbered z-indexes are stacked underneath this layer. The value of zIndex must be 0 or a positive integer.
Methods
captureEvents
Sets the window or document to capture all events of the specified type.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
captureEvents(eventType)
Parameters
eventType |
Type of event to be captured. Available event types are listed with event.
|
Description
When a window with frames wants to capture events in pages loaded from different locations (servers), you need to use captureEvents in a signed script and precede it with enableExternalCapture. For more information and an example, see enableExternalCapture.
captureEvents works in tandem with releaseEvents, routeEvent, and handleEvent. For more information, see "Events in Navigator 4.0".
handleEvent
Invokes the handler for the specified event.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
handleEvent(event)
Parameters
event | Name of an event for which the specified object has an event handler. |
Description
handleEvent works in tandem with captureEvents, releaseEvents, and routeEvent. For more information, see "Events in Navigator 4.0".
load
Changes the source of a layer to the contents of the specified file and simultaneously changes the width at which the layer's HTML contents are wrapped.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
load(sourcestring, width)
Parameters
sourcestring | A string indicating the external file name. |
width | The width of the layer as a pixel value. |
moveAbove
Stacks this layer above the layer specified in the argument, without changing either layer's horizontal or vertical position. After re-stacking, both layers will share the same parent layer.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
moveAbove(aLayer)
Parameters
aLayer | The layer above which to move the current layer. |
moveBelow
Stacks this layer below the specified layer, without changing either layer's horizontal or vertical position. After re-stacking, both layers will share the same parent layer.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
moveBelow(aLayer)
Parameters
aLayer | The layer below which to move the current layer. |
moveBy
Changes the layer position by applying the specified deltas, measured in pixels.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
moveBy(horizontal, vertical)
Parameters
horizontal | The number of pixels by which to move the layer horizontally. |
vertical | The number of pixels by which to move the layer vertically. |
moveTo
Moves the top-left corner of the window to the specified screen coordinates.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
moveTo(x-coordinate, y-coordinate)
Parameters
x-coordinate | An integer representing the top edge of the window in screen coordinates. |
y-coordinate | An integer representing the left edge of the window in screen coordinates. |
Security
To move a window offscreen, call the moveTo method in a signed script. For information on security in Navigator 4.0, see Chapter 7, "JavaScript Security," in the JavaScript Guide.
Description
Changes the layer position to the specified pixel coordinates within the
containing layer. For ILayers, moves the layer relative to the natural inflow
position of the layer.
See also
Layer.moveBy
moveToAbsolute
Changes the layer position to the specified pixel coordinates within the page (instead of the containing layer.)
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
moveToAbsolute(x, y)
Parameters
x | An integer representing the top edge of the window in pixel coordinates. |
y | An integer representing the left edge of the window in pixel coordinates. |
Description
This method is equivalent to setting both the pageX and pageY properties of the layer object.
releaseEvents
Sets the window or document to release captured events of the specified type, sending the event to objects further along the event hierarchy.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
releaseEvents(eventType)
Parameters
eventType | Type of event to be captured. |
Description
If the original target of the event is a window, the window receives the event even if it is set to release that type of event. releaseEvents works in tandem with captureEvents, routeEvent, and handleEvent. For more information, see "Events in Navigator 4.0".
resizeBy
Resizes the layer by the specified height and width values (in pixels).
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
resizeBy(width, height)
Parameters
width | The number of pixels by which to resize the layer horizontally. |
height | The number of pixels by which to resize the layer vertically. |
Description
This does not layout any HTML contained in the layer again. Instead, the layer contents may be clipped by the new boundaries of the layer. This method has the same effect as adding width and height to clip.width and clip.height.
resizeTo
Resizes the layer to have the specified height and width values (in pixels).
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Description
This does not layout any HTML contained in the layer again. Instead, the layer contents may be clipped by the new boundaries of the layer.
Syntax
resizeBy(width, height)
Parameters
width | An integer representing the layer's width in pixels. |
height | An integer representing the layer's height in pixels. |
Description
This method has the same effect setting clip.width and clip.height.
routeEvent
Passes a captured event along the normal event hierarchy.
| Method of |
Layer
|
| Implemented in | Navigator 4.0 |
Syntax
routeEvent(event)
Parameters
event | The event to route. |
Description
If a subobject (document or layer) is also capturing the event, the event is sent to that object. Otherwise, it is sent to its original target.
routeEvent works in tandem with captureEvents, releaseEvents, and handleEvent. For more information, see "Events in Navigator 4.0".
Last Updated: 10/31/97 12:31:11