There's an easy quick fix for this: All you have to do is to tell Photoshop to force all colors to sRGB. You can see a video on how to do this here:
It turns out that while sRGB is the preferred profile for viewing an image on ALL web browsers safely, it is NOT optimal for your working color space. See this page: http://www.luminous-landscape.com/tutorials/prophoto-rgb.shtml/ Basically, the ProPhotoRGB setting that Adobe Lightroom uses by default is the best choice as it has the highest color range. Using sRGB during your workflow may clip some colors where ProPhoto would not.
Thus, I think the best mode to be in is to bring your photos into Photoshop and work in ProPhoto, but finally export them in sRGB (see here for how to do this in LR and PS: http://om4.com.au/client/preparing-images-color-profiles-srgb-adobe-rgb/) so that you can be assured that they display on ALL web browsers safely.