AJAX - The Complete Reference

574 Part IV: Appendixes

• If two strings are identical up to the nth (possibly 0th) character then the (n + 1)st
  character is examined. For example, the third character of “abc” and “abd” would
  be examined if they were to be compared.


• If the numeric value of the character code under examination in the first string is
  less than that of the character in the second string, the first string is “less than”
  second. The relation “1” < “9” < “A” < “Z” < “a” < “z” is often helpful for
  remembering which characters come “less” than others.

Operator Precedence and Associativity

JavaScript assigns a precedence and associativity to each operator so that expressions will

be well-defined, that is, the same expression will always evaluate to the same value.

Operators with higher precedence evaluate before operators with lower precedence.

Associativity determines the order in which identical operators evaluate. We use the symbol

⊗ to specify an arbitrary operator, so given the expression:

a ⊗ b ⊗ c

a left-associative operator would evaluate:

(a ⊗ b) ⊗ c

while a right-associative operator would evaluate

a ⊗ (b ⊗ c)

Table A-18 summarizes operator precedence and associativity in JavaScript.

Precedence Associativity Operator Operator Meanings

Highest Left ., [ ], () Object property access, array or

object property access, parenthesized

expression

Right ++, ––, –, ~, !,

delete, new, typeof,

void

Pre/post increment, pre/post

decrement, arithmetic negation,

bitwise negation, logical negation,

removal of a property, object creation,

getting data type, undefine or dispose

of a value

Left *, /, % Multiplication, division, modulus

Left +, – Addition (arithmetic) and

concatenation (string), subtraction

Left <<, >>, >>> Bitwise left shift, bitwise right shift,

bitwise right shift with zero fill

Left <, <=, >, >=, in,

instanceof

Less than, less than or equal to,

greater than, greater than or equal

to, object has property, object is an

instance of

TABLE A-18 Precedence and Associativity of JavaScript Operators