清理一个URL中的cookie
NSHTTPCookieStorage* cookies = [NSHTTPCookieStorage sharedHTTPCookieStorage];NSArray* arr_cookies = [cookies cookiesForURL:url];for (NSHTTPCookie* cookie in arr_cookies) {[cookies deleteCookie:cookie];}
清理所有的cookies
NSHTTPCookieStorage *cookieStorage = [NSHTTPCookieStorage sharedHTTPCookieStorage];for (NSHTTPCookie *cookie in [cookieStorage cookies]) {[cookieStorage deleteCookie:cookie];}