In CNZZ statistics, JavaScript code is added to every page of a website. When a user browses the page and the page is loaded successfully, statistics are collected through the JavaScript code. Statistics cannot be collected if a page fails to load or if the JavaScript code is not included in the page. Statistics also fail if a file or some images of the website are referenced by other websites. Alibaba Cloud CDN statistics are more comprehensive than CNZZ statistics because data is collected based on every logged access request. If a page contains multiple iframe tags, Alibaba Cloud CDN counts multiple PVs. This is also different from CNZZ statistics.