May 2012
Intermediate to advanced
242 pages
5h 19m
English
Content preview from Maintainable JavaScriptBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Chapter 12. Browser Detection
Browser detection is always a hot-button topic in web development. This battle predates JavaScript browser detection by a couple of years and begins with the introduction of Netscape Navigator, the first truly popular and widely used web browser. Netscape Navigator 2.0 was so far beyond any of the other available web browsers that websites began looking for its specific user-agent string before returning any useful content. This forced other browser vendors, notably Microsoft, to include things in their user-agent string to get around this form of browser detection.
User-Agent Detection
The earliest form of browser detection was user-agent detection, a process by which the server (and later the client) looked at the user-agent string and determined the browser. During that time, servers would regularly block certain browsers from viewing anything on the site based solely on the user-agent string. The browser that benefited the most was Netscape Navigator. Netscape was certainly the most capable browser, so websites targeted that browser as the only one that could properly display the site. Netscape’s user-agent string looked like this:
Mozilla/2.0 (Win95; I)
When Internet Explorer was first released, it was essentially forced to duplicate a large part of the Netscape user-agent string to ensure that servers would serve up the site to this new browser. Because most user-agent detection was done by searching for “Mozilla” and then taking the version number ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.