CSS外边框虚线
The CSS outline property is used to add an outline around an HTML element. By default,the outline is a solid line,but it can also be a dotted or dashed line. To create a dashed outline,use the "outline-style" property with the value "dashed". To create a dotted outline,use the "outline-style" property with the value "dotted". You can also set the width and color of the outline using the "outline-width" and "outline-color" properties. Note that the CSS outline property does not take up space on the page,so it will not affect the layout of your content.
Example:
p {
outline-style: dashed;
outline-width: 1px;
outline-color: #FF0000;
}
This code sets a dashed red outline with a width of 1 pixel around all paragraphs on the page.
