How to solve NaN when I'm deleting a number?

Question

This is the code when I am adding in all textbox it works fine but after removing number it shows NaN:

function sumVal()
{
    var total = 0;
    var coll = document.getElementsByTagName("input")
    for ( var i = 0; i<coll.length; i++)
    {
        var ele = coll[i];
        total += parseInt(ele.value);
    }
    var Display = document.getElementById("Display");
    Display.innerHTML = total;
}

<input onkeyup="sumVal()" />
<input onkeyup="sumVal()" />
<input onkeyup="sumVal()" />

NaN means "Not a Number." The program is trying to tell you it can't parse the input you are giving it. — Robert Harvey, Apr 11 '13 at 15:15
what is parseInt(ele.value) ? It is expecting an integer in the string format — karthikr, Apr 11 '13 at 15:16
Just an aside: You should add a proper `type` attribute value on your ` ` elements (e.g. ``). — Cᴏʀʏ, Apr 11 '13 at 16:05

Chase · Accepted Answer · 2013-04-11T15:29:41.430

Try checking that your value is NaN before adding it to the total:

total += (isNaN(parseInt(ele.value, 10)) ? 0 : parseInt(ele.value, 10));

Also, don't forget the radix for parseInt (or use parseFloat in the event you have decimal places):

radix

An integer that represents the radix of the above mentioned string. Always specify this parameter to eliminate reader confusion and to guarantee predictable behavior. Different implementations produce different results when a radix is not specified.

var nums = [10, "sads", 44, 16];
var numsLen = nums.length;
var total = 0;

while(numsLen--){
    total += (isNaN(parseInt(nums[numsLen], 10)) ? 0 : parseInt(nums[numsLen], 10));
}

In this example, since "sads" is not a number (NaN) we add 0 to the total.

score 2 · Answer 2 · edited May 23 '17 at 12:12

2

You should make sure that the element's value is a valid number first:

if (isNumber(ele.value))
    total += parseInt(ele.value, 10);
}

You'll need this function:

function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

The above function is the famous isNumber function from here.

edited May 23 '17 at 12:12

Community

1
1

answered Apr 11 '13 at 15:18

Cᴏʀʏ

105,112
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score 1 · Answer 3 · answered Apr 11 '13 at 15:16

1

Just add 0 is if it's not a number:

var theInt = parseInt(ele.value, 10);
total += (isNaN(theInt)) ? 0 : theInt;

answered Apr 11 '13 at 15:16

BenM

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How to solve NaN when I'm deleting a number?

3 Answers3