JavaScript Comparison Operations Logic Operators with Booleans
Example
var x = true,
y = false;
AND
This operator will return true if both of the expressions evaluate to true. This boolean operator will employ short-circuiting and will not evaluate y if x evaluates to false.
x && y;
This will return false, because y is false.
OR
This operator will return true if one of the two expressions evaluate to true. This boolean operator will employ short-circuiting and y will not be evaluated if x evaluates to true.
x || y;
This will return true, because x is true.
NOT
This operator will return false if the expression on the right evaluates to true, and return true if the expression on the right evaluates to false.
!x;
This will return false, because x is true.
