How can i detect hi-lights above 250 using JavaScript

HI everyone

i have an script that deletes alpha channels, paths, layer comps, flat the image, change color mode, set resolution to 300 ppi and so on, but now I need to make a selection or at list detect highlights above 250 in RGB channels and also I need to find a way to change the "color profile" from X profile to "Adobe RGB 1998"

Thanks