Is there a font format that supports non-closed outlines?

Question

Fonts

Hello.
I'm looking for a font format supported by modern browsers that would allow characters with open outlines to be contained.
What I mean:

The letter S is made by one curve, but when rendering the ttf font, the closing line of the beginning and end will be automatically added, i.e. it will look the same as the gray fill in the picture. I need to avoid this and without crutches with a very close placement of the second circuit for the actual closure.