NSArray * types =@[WKWebsiteDataTypeMemoryCache,WKWebsiteDataTypeDiskCache]; // iOS 9.0以后
NSSet *websiteDataTypes = [NSSet setWithArray:types];
NSDate *dateFrom = [NSDate dateWithTimeIntervalSince1970:0];
[[WKWebsiteDataStore defaultDataStore] removeDataOfTypes:websiteDataTypes modifiedSince:dateFrom completionHandler:^{
}];