border-image-slice - CSS 3

The border-image-slice property specifies how to slice the image specified by
border-image-source. The image is 
always sliced into nine sections: four corners, four edges and the middle.The "middle" part is treated as 
fully transparent, unless the fill keyword is set.Tip: Also look at the border-image property 
(a shorthand property for setting all the border-image-* properties).

Syntax

border-image-slice: number|%|fill|initial|inherit;

Example

#borderimg {    
	border-image-slice: 30;
	}

Output / Return Value

Limitations

Alternatives / See Also

Reference