The background-clip property defines how far the background image or color should extend within its border-box, padding-box, or content-box only.

Consider the following:

• The border-box value extends the background to the element's borders
• The padding-box value extends it to the inner side of borders
• The content-box value defines the background so that it doesn't go beyond its content area

Essentially, this property has no effect if the background color or background image aren't specified.