The background-clip property is used in CSS and certain HTML elements. It specifies whether an element's background, either the color or image, extends underneath its border. If there is no background-image, this property only has a visual effect when the border has transparent regions (because of border-style) or partially opaque regions; otherwise the border covers up the difference.
Values[]
border-box- Default value. The background extends to the outside edge of the border (but underneath the border in z-ordering). Useborderinstead for compatibility with older versions of Gecko. (Requires Gecko 2.0)padding-box-No background is drawn below the border (background extends to the outside edge of the padding). Usepaddinginstead for compatibility with older versions of Gecko. (Requires Gecko 2.0)content-box- The background is painted within (clipped to) the content box. (Requires Gecko 2.0)