October 2006
Beginner to intermediate
352 pages
9h 33m
English
Content preview from Learning 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 8. The Sandbox and Beyond: Cookies, Connectivity, and Piracy
JavaScript achieved its early popularity in part because of the assurances of the language’s safety. After all, JavaScript in browsers operates within a sandbox—a protective environment that stringently restricts access to the client’s machine. There are no mechanisms to open or create files; the language operates within a temporary environment, which is discarded as soon as the browser terminates or a web page is exited; if data is transmitted, the user is informed; and so on.
We learned over time that there is no way to completely protect the client machines, not when there are determined hackers ready to exploit even the smallest openings in browser or language. The only way to prevent this type of access is to completely close off the client machine from browser access, which makes the browser less than useful. After all, some of the more popular features of browsers are bookmarks, plug-ins and extensions, and remembering URLs and form-field entries. All of these require putting something on the client’s machine; many require the use of cookies.
Cookies: hate them, love them. Cookies are bits of data storage on the client based on key information, provided by the server, that allows JavaScript developers to persist information either during a session (until a browser is closed), or between sessions (web accesses). The original concept was that only those requests to get or write cookies associated with the web ...
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.