Section 22nd Layer

A layer is a page element that is used for precise positioning. Can add images, text and other page elements to the layer, with the help of layers, can be added to the page elements for accurate positioning, but also to make overlapping effects and movement effects.

To add a layer to the page, click on the Objects Panel icon, move the mouse to the Dreamweaver main window, the mouse is displayed as a cross. Drag the mouse over the window area to draw the layer. Alternatively, by clicking on the Insert\ Layer of the menu bar, the main window is added to a layer.

Click on the edge of the layer, that is, select this layer.
Select this layer and use the mouse to drag to move the layer to the appropriate location on the page. Drag the black square on the edge of the mouse to adjust the size of the layer. Click anywhere in the layer with the mouse to add text, images, etc. to the layer.
Layers can be nested in a layer. The practice is to click the inside of a layer with the mouse, click on the Insert\layer of the menu bar, or drag the icon on the objects panel to this layer. The practice of putting an existing layer into another layer is to hold down the CTRL key and drag the layer onto the top of the other layer on the Level Panel.

The properties panel of the layer is shown in the following illustration.

(The Properties panel of the layer) explains the items on the panel below.
Layer ID After you fill in the name of this layer.
The L and T are the positions of the layers, that is, the position in the page. Just mentioned the position of the layer can be dragged by the mouse, in fact, here can also be filled in the L and T after the value and units. L fill in the distance from the left border of the browser window to the left of the layer, and then fill in the distance from the top edge of the browser window. Value to take the unit, the unit generally with PX. Suppose to fill in 200px, indicating a distance of 200 pixel units.
Z-index is the z-value of the page element, followed by a numeric value. When page elements overlap because of positioning, page elements with large z values appear on the surface, overwriting or partially overwriting page elements with a small Z value.
Vis is to set whether the page element is visible. No setting is certainly visible. The next Drop-down selection box has four options--default, inherit, visible, and hidden. Default is to use browser defaults, which are generally visible. Inherit is the visual setting that inherits the parent element, visible is visual and hidden is invisible.
Bg image is the background of this layer setting.
Bg color is the background color that sets this layer.
tag is the HTML tag that should be used for this layer, followed by a Drop-down marquee with spans, DIV, layer, and Ilayer. It is recommended that you select Div so that the General browser can support this layer.
Overflow is how to handle the width or height of the elements in the insertion layer beyond the layer itself. The next Drop-down selection box has four options--visible, hidden, scroll, and auto. Visible is visual, hidden is not viewable, scroll is scrollable and auto is by default in the browser. The clip in the lower right of the dialog box has L, T, R, and b four items.
Clip is to place the page element in the insertion layer by qualifying an area in the middle of the layer. L is the distance from the left side of the clip area to the left of the layer, T is the distance from the top of the clip region, R is the distance to the right of the clip area, and B is the distance from the bottom of the clip area below the location area.
In fact, the various settings of the layer, the principle is to use CSS for the positioning of HTML tags such as div, background and other attributes settings.


Layer also has a level board, which can be used to set some of the properties of the layer.
Click the window\timeline of the menu bar, or use the shortcut ctrl+f9, that is, the pop-up level board.

(Layer Panel)
All layers of the current page are listed on the Level Panel.
Below name is the name of each layer.
Z Below is the z value of each layer, click this value to modify. The eye icon shows the visibility of each layer below. Click to bring up three states-no icon, open Eye icon and closed eye icon. No icon indicates that the visibility of the layer uses the default value, and the open Eye icon indicates that the layer is visible, and the closed eye icon indicates that the layer is not seen.
Select the marquee on the Prevent overlaps of the panel, then there is no overlap between the layers, and no nesting layer can be nested in the layer.