April 2007
Intermediate to advanced
1728 pages
47h 51m
English
Content preview from JavaScript® Bible, Sixth EditionBecome 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,
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Chapter 32. Control Structures and Exception Handling
IN THIS CHAPTER
Branching script execution down multiple paths
Looping through ordered collections of data
Applying exception handling techniques
You get up in the morning, go about your day's business, and then turn out the lights at night. That's not much different from what a program does from the time it starts to the time it ends. But along the way, both you and a program take lots of tiny steps, not all of which advance the processing in a straight line. At times, you have to control what's going on by making a decision or repeating tasks until the whole job is finished. Control structures are the facilities that make these tasks possible in JavaScript.
JavaScript control structures follow along the same lines of many programming languages. Basic decision-making and looping constructions satisfy the needs of just about all programming tasks.
Another vital program control mechanism—error (or exception) handling—is formally addressed in Edition 3 of the ECMA-262 language standard. The concept of exception handling was added to the JavaScript version introduced in IE5.5 and NN6, but it is well known to programmers in many other environments. Adopting exception-handling techniques in your code can greatly enhance recovery from processing errors beyond your control, such as those caused by errant user input or network glitches.
If and If. . .Else Decisions
Compatibility: WinIE3+, MacIE3+, NN2+, Moz+, Safari+
JavaScript programs frequently ...
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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.