how to identify var in javascript only numbers code example

Example 1: check if input is a number javascript

// Another option is typeof which return a string
if (typeof(val) === 'number') {
	// Guess what, it's a bloody number!
}

Example 2: if parameter is not number in js

let num1 = 'Hello';
if(isNaN(num1)){
    console.log(num1 + ' is not a number');
} else{
    console.log(num1 + ' is a number');
}