April 2007
Intermediate to advanced
1728 pages
47h 51m
English
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Chapter 30. The Date Object
IN THIS CHAPTER
Working with date and time values in JavaScript
Performing date calculations
Validating date entry form fields
Perhaps the most untapped power of JavaScript is its date and time handling. Scripters passed over the Date object with good cause in the early days of JavaScript, because in earlier versions of scriptable browsers, significant bugs and platform-specific anomalies made date and time programming hazardous without significant testing. Even with the improved bug situation, working with dates requires a working knowledge of the world's time zones and their relationships with the standard reference point, known as Greenwich Mean Time (GMT) or Coordinated Universal Time (abbreviated UTC).
Now that date- and time-handling has stabilized in modern browsers, I hope more scripters look into incorporating these kinds of calculations into their pages. In Chapter 54 on the CD-ROM, for example, I show you an application that lets your web site highlight the areas that have been updated since each visitor's last surf ride through your pages—an application that relies heavily on date arithmetic and time zone conversion.
Before getting to the JavaScript part of date discussions, however, the chapter summarizes key facts about time zones and their impact on scripting date and time on a browser. If you're not sure what GMT and UTC mean, the following section is for you.
Time Zones and GMT
By international agreement, the world is divided into distinct time ...
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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.
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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.