border-image: xx xx xx is shorthand for a series of parameters of the property as a picture frame modification
border-image-source: url (border.png); picture url address
border-image-slice: 20% 20% 20% 20%; image slice position, four cut lines of the picture frame 9 house. Up, left, down, right adjustable corners follow the changes, remove center
border-image-width: 10px 10px 10px 10px; pictures, left, bottom, right slice width
border-image-outside: 0px 0px 0px 0px; filling frame from the upper and lower left and right images
border-image-repeat: repeat round; tiled image in the horizontal and vertical directions
border-image: source slice width outset repeat; 简写