Comparison and logical operators are used to test true or false.
Comparison Operators
Comparison operators are used in logical statements to determine whether variables or values are equal.
Given x = 5, the following table explains the comparison operators:
Operator |
Description |
Example |
= |
Equal |
X = 8 is false |
=== |
Full (Value and type) |
X = 5 is true; x = "5" is false |
! = |
Not equal |
X! = 8 is true |
> |
Greater |
X> 8 is false. |
< |
Less |
X <8 is true |
> = |
Greater than or equal |
X> = 8 is false |
<= |
Less than or equal |
X <= 8 is true |
How to Use
You can use a comparison operator in a condition statement to compare values and then take actions based on the results:
If (age <18) document. write ("Too young ");
In the next section of this tutorial, you will learn more about conditional statements.
Logical operators
Logical operators are used to determine the logic between variables or values.
Given x = 6 and y = 3, the following table describes the logical operators:
Operator |
Description |
Example |
&& |
And |
(X <10 & y> 1) is true |
| |
Or |
(X = 5 | y = 5) false |
! |
Not |
! (X = y) is true |
Conditional Operators
JavaScript also contains conditional operators that assign values to variables based on certain conditions.
Syntax
Variablename = (condition )? Value1: value2
Example
Greeting = (visitor = "PRES ")? "Dear President": "Dear ";
If the value in the variable visitor is "PRES", the value of "Dear President" is assigned to the variable greeting; otherwise, the value of "Dear" is assigned ".