Why it alert's string when you enter a number.? | Sololearn: Learn to code for FREE!

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Why it alert's string when you enter a number.?

https://code.sololearn.com/WTPojwGulhn4/?ref=app

4/18/2018 8:45:34 AM

Sina

8 Answers

New Answer

+2

It's the default return type from a prompt. I'd suggest to use the isNaN statement to test (is Not a Number), which understands if the value of the variable is not usable as a number. Just add the not logical operator (!) and you've done. function a() { var b = prompt("Enter s.th"); var type; if (!isNaN(b)) type = 'It is a Number!'; else type = 'It is a String!'; alert(type); } a()

+2

because the default value of a type of data received in a prompt is string

+1

Obviously we can reverse the code to be more straightforward: if (isNaN(b)) type = 'It is a String!'; else type = 'It is a Number!';

+1

Yes I underestood thanks

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Ok thanks

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I have a question you wrote if(!isNaN(b)){ type="it's a number" } it means if b is not a number

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Please note the ! before the isNaN statement, that means it will reverse the value of isNaN(b). // User wrote 7 isNaN(b) = false !isNaN(b) = true //User wrote “hello” isNaN(b) = true !isNaN(b) = false

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Ok