javascript 权威指南 学习笔记3:Equality (==) and Identity (===)

== operator is known as the equality operator; it checks whether its two operands are "equal" using a more relaxed definition of sameness that allows type conversions.

=, "is equal to" for ==, and "is identical to" for ===.

!== stands for "not identical to." See the previous section for details on how equality and identity are defined for different data types.