Comparison and Logical operators are used to
test for true or false.
Comparison
Operators
Comparison operators are used in logical
statements to determine equality or difference between variables or values.
Given that x=5, the table below explains
the comparison operators:
|
Operator
|
Description
|
Comparing
|
Returns
|
|
==
|
equal to
|
x == 8
|
false
|
|
x == 5
|
true
|
||
|
===
|
exactly equal to (equal value and equal type)
|
x === "5"
|
false
|
|
x === 5
|
true
|
||
|
!=
|
not equal
|
x != 8
|
true
|
|
!==
|
not equal (different value or different type)
|
x !== "5"
|
true
|
|
x !== 5
|
false
|
||
|
>
|
greater than
|
x > 8
|
false
|
|
<
|
less than
|
x < 8
|
true
|
|
>=
|
greater than or equal to
|
x >= 8
|
false
|
|
<=
|
less than or equal to
|
x <= 8
|
true
|
How can
it be used
Comparison operators can be used in
conditional statements to compare values and take action depending on the
result:
if (age < 18) text
= "Too young";
You will learn more about the use of
conditional statements in the next chapter of this tutorial.
Logical
Operators
Logical operators are used to determine the
logic between variables or values.
Given that x=6 and y=3, the table
below explains the logical operators:
|
Operator
|
Description
|
Example
|
|
&&
|
and
|
(x < 10 && y > 1) is true
|
|
||
|
or
|
(x == 5 || y == 5) is false
|
|
!
|
not
|
!(x == y) is true
|
Conditional
Operator
JavaScript also contains a conditional
operator that assigns a value to a variable based on some condition.
Syntax
variablename=(condition)?value1:value2
Example
If the variable age is
a value below 18, the value of the variable voteable will be
"Too young", otherwise the value ofvoteable will be
"Old enough":
voteable = (age < 18)
? "Too young":"Old enough";
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