Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How do you check that a number is NaN in JavaScript?
NaN is a JavaScript property, which is Not-a-Number value. This shows it is not a legal number. Here’s the syntax −
Syntax
Number.NaN
To find out whether a number is NaN, use the Number.isNaN() or isNan() method. Here’s an example to check −
Example
<!DOCTYPE html>
<html>
<body>
<button onclick="display()">Check</button>
<p id="test"></p>
<script>
function display() {
var a = "";
a = a + isNaN(434) + ": 434<br>";
a = a + isNaN(-23.1) + ": -23.1<br>";
a = a + isNaN('Hello') + ": 'Hello'<br>";
a = a + isNaN(NaN) + ": NaN<br>";
a = a + isNaN('') + ": ''<br>";
a = a + isNaN(0) + ": 0<br>";
a = a + isNaN(false) + ": false<br>";
document.getElementById("test").innerHTML = a;
}
</script>
</body>
</html>
Updated on: 17-Jun-2020
161 Views
Advertisements