on contour in limited z range

hello, matlab pepole

while I use "surf" to create x,y,z 3D surface,where z=z(x,y), then I want to get the "contour" of the surf, but I just want to get the contour between "z=10 and z=20", at the same time I want to give the "colorbar" of this kind of contour.

please help

any suggestion, any help

Thank you