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Matthew Keys
1,922 PointsExplanation of the slash after the image position
Can someone please explain to me why you need to put a slash after the image position (center / cover)?
1 Answer
Jason Anello
Courses Plus Student 94,610 PointsHi Matthew,
This is a syntax requirement to remove ambiguity that would occur without it.
background-position and background-size can both accept some of the same types of values. For example, percentages and lengths.
Imagine the following background shorthand was used:
background: 30% 80%;
This can be interpreted multiple ways if we didn't have that forward slash syntax requirement. Are both of those values for the background-position? Are both for background-size? Is one for background-position and the other for background-size?
To remove this uncertainty, it was decided that background-position would be first, then a forward slash, and then the background-size.
This syntax also means that it's not possible to specify the background-size without also first specifying the background-position using the shorthand.
Going back to the earlier example, because the browser does not see a forward slash followed by values for background-size, it knows that the 30% 80% is for background-position. There is no other way to interpret it.