If pakistan is attcked by usa?will china react?

china always has deep intrests with pakistan.accroding to surverys(geo network pk) 90% of pakis support china as super power.moreover islamic scholars(from pakistan) believe that God permits relations with communits and orders to fight christians n jews.pakistan is almost at verge at war with usa if musharaf goes home.pakis belive usa is abt to wipe them off but chinese side has been continously warning world saying pakistan is thier all time best friend(or in other words saying they would fight too).its china who made pakis nuclear power and pakis gave nuclear tech to north korea(as thanks).pakis have been also sharing nuklar tech with iran(part of deal).seeing chinese mive investments in pakisan and deep ties.and pakis gave part of kashmir to china during 1965 war with india as a gift.chinese allowed air space use to paki airforce during 1965 wars and 1971 war w/india.would china react if pakistan is conquered by usa or just watch it and do nothing.