JavaScript Comparison and Logical Operators
JavaScript Comparison and Logical Operators
- 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 | Name | Example | Return Value |
|---|---|---|---|
| == | Equal to | a==b | True or false |
| a==3 | True or false | ||
| a=="3" | True or false | ||
| === | Equal value and types | a===b | True or false |
| a===="3" | True or false | ||
| != | Not equal to | a!=b | True or false |
| !== | Not equal to and types | a!==b | True or false |
| a!=="b" | True or false | ||
| > | Greater than | a>b | True or false |
| < | Less than | a<b | True or false |
| >= | Greater than or equal to | a>=b | True or false |
| <= | Less than or equal to | a<=b | True or false |
How Can it be Used
- The Comparison operators can be used in conditional statements to compare values and take action depending on the result:
if (age < 18) text = "Too young to buy alcohol";Logical Operators
- Logical operators are used to determine the logic between variables or values.
| Operator | Description | Example |
|---|---|---|
| && | AND | (x < 10 && y > 1) is true |
| || | OR | (x == 5 || y == 5) is false |
| ! | NOT | !(x == y) is true |
Syntax
let voteable = (age < 18) ? "Too young":"Old enough";
Sample Code
<!DOCTYPE html>
<html>
<body>
<h1>JavaScript Comparison</h1>
<h2>The () ? : Ternary Operator</h2>
<p>Input your age and click the button:</p>
<input id="age" value="18" />
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
let age = document.getElementById("age").value;
let voteable = (age < 18) ? "Too young":"Old enough";
document.getElementById("demo").innerHTML = voteable + " to vote.";
}
</script>
</body>
</html>
Output
