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Layer
Corresponds to a layer in an HTML page and provides a means for manipulating that layer.
创建源
The HTML LAYER or ILAYER tag, or using cascading style sheet语法. 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语法. If you specify the ID attribute, you can use the value of that attribute to index into the layers array.
For a complete描述 of layers, see Dynamic HTML in Netscape Communicator.
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.
事件句柄
属性概览
| 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. | | background | The image to use as the background for the layer's canvas. | | bgColor | The color to use as a solid background color for the layer's canvas. | | 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. | | clip.bottom | The bottom edge of the clipping rectangle (the part of the layer that is visible.) | | clip.height | The height of the clipping rectangle (the part of the layer that is visible.) | | clip.left | The left edge of the clipping rectangle (the part of the layer that is visible.) | | clip.right | The right edge of the clipping rectangle (the part of the layer that is visible.) | | clip.top | The top edge of the clipping rectangle (the part of the layer that is visible.) | | clip.width | The width of the clipping rectangle (the part of the layer that is visible.) | | document | The layer's associated document. | | left | The horizontal position of the layer's left edge, in pixels, relative to the origin of its parent layer. | | name | A string specifying the name assigned to the layer through the ID attribute in the LAYER tag. | | pageX | The horizontal position of the layer, in pixels, relative to the page. | | page y | The vertical position of the layer, in pixels, relative to the page. | | parentLayer | The layer object that contains this layer, or the enclosing window object if this layer is not nested in another layer. | | 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. | | 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. | | src | A string specifying the URL of the layer's content. | | top | The vertical position of the layer's top edge, in pixels, relative to the origin of its parent layer. | | visibility | Whether or not the layer is visible. | | zIndex | The relative z-order of this layer with respect to its siblings. |
方法概览
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.
属性
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.
background
The image to use as the background for the layer's canvas (which is the part of the layer within the clip rectangle).
描述
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).
描述
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".
示例
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"
参看
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.
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.
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.
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.
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.
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.
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.
document
The layer's associated document.
描述
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.
name
A string specifying the name assigned to the layer through the ID attribute in the LAYER tag.
pageX
The horizontal position of the layer, in pixels, relative to the page.
pageY
The vertical position of the layer, in pixels, relative to the page.
parentLayer
The layer object that contains this layer, or the enclosing window object if this layer is not nested in another layer.
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.
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.
src
A URL string specifying the source of the layer's content. Corresponds to the SRC attribute.
top
The top property is a synonym for the topmost Navigator window, which is a document window or web browser window.
描述
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 objectReference>
where objectReference is an internal reference.
示例
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.
描述
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.
描述
Sibling layers with lower numbered z-indexes are stacked underneath this layer. The value of zIndex must be 0 or a positive integer.
方法
captureEvents
Sets the window or document to capture all events of the specified type.
语法
captureEvents(eventType)
参数
描述
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
调用指定事件的控制句柄。
语法
handleEvent(event)
参数
描述
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.
语法
load(sourcestring, width)
参数
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.
语法
moveAbove(aLayer)
参数
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.
语法
moveBelow(aLayer)
参数
moveBy
Changes the layer position by applying the specified deltas, measured in pixels.
语法
moveBy(horizontal, vertical)
参数
moveTo
Moves the top-left corner of the window to the specified screen coordinates.
语法
moveTo(x-coordinate, y-coordinate)
参数
安全性
To move a window offscreen, call the moveTo method in a signed script. 要获取 Navigator 4.0 中关于安全性更多的信息，请看“JavaScript 指南”中的第七章“JavaScript 安全性”。
描述
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.
参看
Layer.moveBy
moveToAbsolute
Changes the layer position to the specified pixel coordinates within the page (instead of the containing layer.)
语法
moveToAbsolute(x, y)
参数
描述
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.
语法
releaseEvents(eventType)
参数
描述
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).
语法
resizeBy(width, height)
参数
描述
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).
描述
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.
语法
resizeBy(width, height)
参数
描述
This method has the same effect setting clip.width and clip.height.
routeEvent
Passes a captured event along the normal event hierarchy.
语法
routeEvent(event)
参数
描述
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".
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