All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Your husband conditioned divorce on your going to the hair saloon, so if you go, divorce takes place according to the majority of the jurists whether he intended divorce or intended something else. The matter is in your hand so you must be careful. Even if you go out with his knowledge and permission divorce still takes place, unless if he means if you go to the hair saloon without his knowledge then in this case if you go with his knowledge you are not divorced.
In principle the wife has to obey her husband in everything as long as he does not order her to disobey Allaah. What he has prevented you from could be a benefit for you in relation to your religion and worldly matters. Finally, we remind you to be cautious about anything that could cause division, divorce and the breaking up of the family.
Allaah knows best.