In practice, it is probably best to include it as an image or part of image,
since writing it as a character isn't very successful.
It's in the Musical Symbols block,
http://www.unicode.org/charts/PDF/U1D100.pdf
You probably mean MUSICAL SYMBOL RIGHT REPEAT SIGN U+1D107, which could be
written in HTML as . But according to
http://www.fileformat.info/info/unicode/char/1d107/fontsupport.htm
the only font containing the sign is Code2001, which is both rare (though
freely available) and typographically awful (especially when font smoothing
is not enabled). For this character, the typography part is not a problem,
but the problem is that most computers don't contain Code2001.
Besides, making Unicode characters outside the Basic Multilingual Plane
(i.e., characters with code numbers > FFFF in hexadecimal) work on browsers
is, at best, possible only through quite some kludgery; see
http://www.i18nguy.com/unicode-example-plane1.html