Logical Operators
Logic operators are used to find the logic between variables in JavaScript.There are three logical operators in JavaScript: || (OR), && (AND), ! (NOT).
The AND operator
The AND operator (&&) returns true if both expressions are true, otherwise it returns false.
Example
<html>
<body>
<p id="and"></p>
<script>
var a = 200;
var b = 300;
document.getElementById("and").innerHTML =
(a > 100 && b <500) + "<br>" +
(a < 100 && b <50);
</script>
</body>
</html>Output
true false
The OR operator
The OR operator gives value true if one or both expressions are true.
Example
<html>
<body>
<p id="or"></p>
<script>
var x = 200;
var y = 300;
document.getElementById("or").innerHTML =
(x == 200 || y == 300) + "<br>" +
(x == 200 || y == 0) + "<br>" +
(x == 0 || y == 0)
</script>
</body>
</html>Output
true true false
The NOT operator
The NOT operator gives false for true values and true for false values.
Example
<html>
<body>
<p id="not"></p>
<script>
var x = 200;
var y = 300;
document.getElementById("not").innerHTML =
!(x < y) + "<br>" + !(x > y);
</script>
</body>
</html>Output
false true