You can learn more about the online manual in this tour. Also, here's the public home page for the Chicago Manual of Style. Available there is the free Chicago Style Q&A that I highlight monthly in my blog:
The Chicago Manual of Style Online includes the popular Chicago Style Q&A, a resource that thousands have found entertaining and informative. The Q&A content is fully searchable along with the content of The Chicago Manual of Style. Your queries will return results—clearly distinguishable—from both the Manual and the Chicago Style Q&A. The Chicago Style Q&A also features monthly polls and interviews of interest to anyone who works with words.I subscribed to Chicago's online manual for a while and found it easy to use. The less-comprehensive Associated Press Stylebook is usually my first-choice writing guide (from my training and experience in journalism). It also provides an online version by subscription.
BTW, I'm not compensated by either company for providing this information. You're also welcome to visit my free online guide, Garbl's Editorial Style and Usage Manual.
The Chicago website is featured today in the March 23 edition of my free online daily paper, Garbl's Style: Write Choices, available at the Editorial Style tab above and by free email subscription.