A JPEG question

I wonder if anyone can help me with this question.

When I save a jpeg of an image in Photoshop the image appears considerably lighter and less saturated when viewed in a web
browser. The detail seems fine, just the color and darkness are affected - even if I save in the highest quality setting. I usually increase the values for hue and saturation in the original to compensate, but even so I don't get close to the character of the original image. Is there a setting that I am missing when I save the image?

thanks,
Alan