cant connect to facbook please help!!!

hi ,i couldn't connect to facebook suddenly.
interestingly,all sites like youtube,twitter,and.... are opening when i brows them but facebook does not loaded when i brows it. another point is that when i used other browser like firefox or opera,my homepage in facebook was loaded ,but just one time and one page,and when i wanted to see my another page ,it didn't load ,and my homepage also didn't loaded again.
all of my browser now cant connect to facebook.
what is this problem!?i had never been in such trouble for 3 years after switching to mac os!!

can you tell us what browser are you using that will not show fb? is it safary?

yes im using safari for network connection,but non of my browser ,safari,firefox,opera can not connect facebook