Javascript gaJsHost

i just want to 开发者_如何学JAVAknow the use of this script..

 var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");

 document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));

i found this on some websites.. :)

and also this one..

 var pageTracker = _gat._getTracker("UA-1965499-1");

 pageTracker._initData();

 pageTracker._trackPageview();

Its Google Analytics tracker code.

Quote from this link: http://www.google.com/support/analytics/bin/answer.py?hl=en&answer=55591

Google Analytics shows you how people found your site, how they explored it, and how you can enhance their visitor experience. With this information, you can improve your website return on investment, increase conversions, and make more money on the web. This guide can help you familiarize yourself with the main features of Google Analytics.

Now, this page suggest the use of your mentioned code: http://www.google.com/support/analytics/bin/answer.py?hl=en&answer=55488

Though, this is the old (traditional) method. Google introduced new asynchronous method for adding tracker code.