How to use isNaN() Function In Javascript
The isNaN() function in JavaScript checks if a value is “Not-a-Number” (NaN). By converting a string to a number using parseFloat(), it can determine if the string contains only digits. If the conversion is successful, it returns false, indicating that the string contains only digits. Otherwise, it returns true.
Example: The containsOnlyDigits function checks if a string contains only digits by attempting to convert it to a number using parseFloat(). It returns true if successful, indicating the string contains only digits, otherwise false.
function containsOnlyDigits(str) {
return !isNaN(str) && !isNaN(parseFloat(str));
}
console.log(containsOnlyDigits("123")); // Output: true
console.log(containsOnlyDigits("123abc")); // Output: false
Output
true false
How to check if string contains only digits in JavaScript ?
Checking if a string contains only digits in JavaScript involves verifying that every character in the string is a numerical digit (0-9).