Numbers
JavaScript has a single number type. Internally, it is represented as 64-bit
floating point, the same as Java's double. Unlike
most other programming languages, there is no separate integer type, so 1 and 1.0 are the
same value. This is a significant convenience because problems of overflow in short
integers are completely avoided, and all you need to know about a number is that it
is a number. A large class of numeric type errors is avoided.
If a number literal has an exponent part, then the value of the literal is
computed by multiplying the part before the e by
10 raised to the power of the part after the
e. So 100
and 1e2 are the same number.
Negative numbers can be formed by using the -
prefix operator.
The value NaN is a number value that is the
result of an operation that cannot produce a normal result. NaN is not equal to any value, including itself. You can detect
NaN with the isNaN(
number
) function.
The value Infinity represents all values
greater than 1.79769313486231570e+308.
Numbers have methods (see Chapter 8). JavaScript has a Math object that contains a set of methods ...
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