Difference between != and !== operator in JavaScript

• != operator
  • The inequality operator (!=) is the logical opposite of the equality operator. It means “Not Equal” and returns true where equality would return false and vice versa.
  • Like the equality operator, the inequality operator will convert data types of values while comparing.
  • For example 1 != ‘1’ will return false since data type conversion take place so 1 and ‘1’ are considered equal.
• !== operator
  • The strict inequality operator (!==) is the logical opposite of the strict equality operator. It means “Strictly Not Equal” and returns true where strict equality would return false and vice versa.
  • Strict inequality will not convert data types.
  • For example 1 !== ‘1’ will return true since 1 is an integer and ‘1’ is a character and no data type conversion take place.

Example:

<script>
    function NotEqual(val) {
        if (val != 1) {
            return "Both are Not Equal i.e. condition is true";
        } else {
            return "Both are Equal i.e. condition is false";
        }
    }

function StrictlyNotEqual(val) {
    if (val !== 1) {
        return "Both are Not Equal i.e. condition is true";
    } else {
        return "Both are Equal i.e. condition is false";
    }
}

//Passing integer

console.log("  1 != 1 " + NotEqual(1));
console.log("  1 !== 1 " + StrictlyNotEqual(1));

//Passing character

console.log(" '1' != 1 " + NotEqual('1'));
console.log(" '1' !== 1 " + StrictlyNotEqual('1'));

//Passing string

console.log(" \"1\" != 1 " + NotEqual("1"));
console.log(" \"1\" !== 1 " + StrictlyNotEqual("1"));

//Passing false value i.e. 0

console.log("  0 != 1 " + NotEqual(0));
console.log("  0 !== 1 " + StrictlyNotEqual(0));
</script>

Output:

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