caption.backgroundColor Type: string
Default value: "rgba(0, 5, 10, 0.6)"
Choose the background color of slider caption (in rgb, rgba or html). By default the background color is transparent black!
The left slider caption has blue-transparent color and the other one has red-transparent color. Try it yourself!
Important: Note that an object embedded is necessary to handle the caption options! And remember: don't forget to fill in the data-caption attribute of the tag img!