This page you are looking at is being tested tracking code for Google Analytics.
When you reach this page, it'll send a pageview to GA automaticly,the ga code shows as below:
How it work?
step1_:從GA非同步下載analytics.js tracking library
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
step2_:產生 ga() function 及 tracker 物件
ga('create', 'UA-60781876-2', 'auto');
step3_:透過ga()的send指令送出pageview到GA
ga('send', 'pageview');