How to get proper user defined output when adding a string with a number, instead of NaN?

Question

I am trying to write a Java Script program that should have two variables. You should add and display the sum only if they are numbers. If they are of any other type you should show a message "Sorry.... Only Nos will be added" Please have look in the below snippet. Thanks in advance

<script>
var x = Number(prompt("Enter First Choice"));
var y = Number(prompt("Enter Second Choice"));
var x1 = typeof x;
var y1 = typeof y;

if(x1==='number' && y1==='number'){
document.write(x+y);
}
else{
document.write("Sorry.... Only Nos will be added");
}
</script>

`isNaN` does the trick. – Jack Bashford Apr 19 '19 at 06:28 — Jack Bashford, Apr 19 '19 at 06:28
Use `Number.isNaN` – CertainPerformance Apr 19 '19 at 06:28 — CertainPerformance, Apr 19 '19 at 06:28

Maheer Ali · Answer 1 · 2019-04-19T06:37:37.593

0

Because typeof NaN is number. And NaN === NaN is false you should use isNaN.

var x = Number(prompt("Enter First Choice"));
var y = Number(prompt("Enter Second Choice"));

if(!isNaN(x1) && !isNaN(y1)){
  document.write(x+y);
}
else{
  document.write("Sorry.... Only Nos will be added");
}

I short code will be like.

edited Apr 19 '19 at 06:37

answered Apr 19 '19 at 06:28

Maheer Ali

35,834
5
42
73

@Maheer-Thanks man...I got the point & it's working fine. – Souradip Apr 19 '19 at 06:36
@Souradip Consider accepting the answer if you are satisfied. – Maheer Ali Apr 19 '19 at 06:42

How to get proper user defined output when adding a string with a number, instead of NaN?

1 Answers1