javascript

Chapter 3: Language Basics
Modulus
The modulus (remainder) operator is represented by a percent sign ( % ) and is used in the following way:
var result = 26 % 5; //equal to 1
Just like the other multiplicative operators, the modulus operator behaves differently for special values,
as follows:
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If the operands are numbers, regular arithmetic division is performed, and the remainder of that
division is returned.
If the dividend is Infinity or the divisor is 0, the result is NaN .
If Infinity is divided by Infinity , the result is NaN .
If the divisor is an infinite number, the result is the dividend.
If the dividend is zero, the result is zero.
If either operand isn ’ t a number, it is converted to a number behind the scenes using Number()
and then the other rules are applied.
Additive Operators
Add
The additive operators, add and subtract, are typically the simplest mathematical operators in
programming languages. In ECMAScript, however, a number of special behaviors are associated with
each operator. As with the multiplicative operators, conversions occur behind the scenes for different
data types. For these operators, however, the rules aren ’ t as straightforward.
The add operator ( + ) is used just as one would expect, as shown in the following example:
var result = 1 + 2;
If the two operands are numbers, they perform an arithmetic add and return the result according to the
following rules:
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If either number is NaN , the result is NaN .
If Infinity is added to Infinity , the result is Infinity .
If – Infinity is added to – Infinity , the result is – Infinity .
If Infinity is added to – Infinity , the result is NaN .
If +0 is added to +0, the result is +0.
If – 0 is added to +0, the result is +0.
If – 0 is added to – 0, the result is – 0.
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