Boolean Data Type

We have seen that operators like + , - , *, and / operate on numbers.

   3 * 3   (result is number data type)

We have seen that the + operator has a dual role of concatanation when operating on strings.

  "Scooby " + "Doo"  (result is string data type)

Comparison Operators such as greater than (>) or less than (<) result in neither numeric or string data.

  3 < 4   (result is Boolean data type)

The Boolean data type refers to George Boole, a mathematician who was among the first to formalize the mathematical rules of propositional logic in the early 1800's.
The Boolean Data is either true as in (3 < 4) or false as in (4 < 3).
Boolean values are not strings like "true" or "false", which would simply be 4-character and 5-character strings, respectively.
Boolean values are simply true or false, which can literally be stored in memory in one bit, where 0 is false, and 1 is true.

Below is a full list of comparison operators that result in Boolean values.

    <     less than
    <=    less than or equal to
    >     greater than
    >=    greater than or equal to
    ==    equals (the single equal sign is the variable assignment operator)
    !=    not equals

The Boolean values below result from evaluating JavaScript expressions.
See the script near the bottom of this page to see the actual expressions that generate these values.