Why is my typeof function not detecting numbers right?

Question

https://code.sololearn.com/WIS31gD6py0U/?ref=app

Answer 1

Because the prompt() function converts the output in string.

Try with this, in my CodePlayground works well! ^_^

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

var num = prompt("Enter something");

if (!isNaN(parseFloat(num))) {
alert("it's a number");
} else {
alert("It's not a number");
}

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer 2

Prompt returns a string. So no matter what you put in the text box, 'num' would be a string.

ex/
input : 7
then
num = "7"

Answer 3

@ValentinHacker No. Why do you post this when you didn't even try it??

prompt always returns a string, so you have to convert num to a number and then check if it is NaN.

var num = Number(prompt("Enter a Number"));

if(isNaN(num)){
alert("It's not a number");
}
else{
alert("It's a number");
}

Answer 4

Thank you very much all!