How can I check if an input is NaN?

Question

I'm trying to check to see if an input is NaN, basically I want to alert 0 if nums doesn't have anything in it, or if that something is a 0. Any ideas on how to go about this?

var sumofnums = 0,
nums = document.getElementById("nums").value.split(",");

function add(){
    for (i = 0; i < nums.length; i++) {
        sumofnums += parseInt(nums[i]);
    };
    document.getElementById("sum").innerHTML = sumofnums;
};
if (nums === ''){
    alert('0');
}

So do the paring into a variable and check if the variable is NaN.... — epascarello, Feb 23 '18 at 01:50
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN — epascarello, Feb 23 '18 at 01:52
Well, it is a little more complicated. You are splitting the input at the comma, but you cannot guarantee that a comma will be used. So there may be other issues. Now, to your question: no, you cannot pass `nums` into `isNaN()` because it is an array. You would pass each of the `nums` elements. — Randy Casburn, Feb 23 '18 at 01:55
@RandyCasburn yes and also I noticed that since there are commas it will register as NaN — Bkes, Feb 23 '18 at 02:01

score -1 · Answer 1 · answered Feb 23 '18 at 01:50

-1

isNaN();

Google can help as well.

answered Feb 23 '18 at 01:50

Deadweight

137
8

Tried this and not as easy as you make it seem – Bkes Feb 23 '18 at 01:51

How can I check if an input is NaN?

1 Answers1