Can't solve NaN error (javascript)

Question

So I made this very basic form with just 4 inputs fields and a submit button with the value and onclick function "calculate".

Then I started coding some javascript for it that looks like this:

function calculate(){
var insert1 = document.getElementById('insert1').value;
var insert2 = document.getElementById('insert2').value;
var insert3 = document.getElementById('insert3').value;
var isnert4 = document.getElementById('insert4').value;

var results = insert1 * insert2 * insert3 * insert4;
document.write(results);
}

So I tested the code by pressing on the submit button and it only displayed "NaN". I noticed that when I change the parameter of the document.write to one of the inserts I don't get the error and it will display the value of the insert. So i think that the issues is in the var result line but i'm not 100% sure.

Maybe try [debugging your code](http://stackoverflow.com/questions/988363/how-can-i-debug-my-javascript-code) — Liam, May 11 '17 at 09:47
You need to provide a real [mcve]. The code you have given will throw a referenceerror, not display NaN (so you haven't verified it). A *complete* example would need to include the HTML and the data you were testing. — Quentin, May 11 '17 at 09:48
Ahhhh, it won't throw a referenceerror because `insert4` et al are globals implicitly created by the input elements. (That would have been more obvious if the [mcve] was complete) — Quentin, May 11 '17 at 10:01
there is a small typo at `var insert4` you wrote typed `var isnert4` thats — Taku_VM, Jun 23 '20 at 18:56

score 0 · Accepted Answer · answered May 11 '17 at 09:55

The reason you're getting a NaN is because attempting to multiply anything with NaN yields another NaN.

Due to a typo in your code:

var isnert4 = document.getElementById('insert4').value; 
     ^ --- here

But attempting to use the variable you intended:

var results = insert1 * insert2 * insert3 * insert4;
                              here ------------^

Means insert4 is NaN and thus the result of the entire calculation is also NaN.

Correct the typo and your code will work as expected.

_{ps. Its 2017, stop using document.write!}

Can't solve NaN error (javascript)

1 Answers1