July 2008
Beginner
356 pages
6h 8m
English
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Primitive Data Types
Any value that you use is of a certain type. In JavaScript, there are the following primitive data types:
- Number—this includes floating point numbers as well as integers, for example 1, 100, 3.14.
- String—any number of characters, for example "a", "one", "one 2 three".
- Boolean—can be either
trueorfalse. - Undefined—when you try to access a variable that doesn't exist, you get the special value
undefined. The same will happen when you have declared a variable, but not given it a value yet. JavaScript will initialize it behind the scenes, with the valueundefined. - Null—this is another special data type that can have only one value, the
nullvalue. It means no value, an empty value, nothing. The difference withundefinedis that ...
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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.