JavaScript NaN Property: Number Object

Last update on April 14 2018 06:14:55 (UTC/GMT +8 hours)

Description

The NaN property of number object represents a value that is not a number. JavaScript prints the value as NaN.

Version

Implemented in JavaScript 1.1

Syntax

Number.NAN

Example:

The following web document demonstrates how the NaN() property can be used.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<title>JavaScript Number object - NAN property example</title>
</head>
<body>
<h1 style="color: red">JavaScript Number object : NAN property</h1>
<hr />
<script type="text/javascript">
//This is done to make the following JavaScript code compatible to XHTML. <![CDATA[
if(123 == Number.NaN)
{
document.write("This is not a number.... " + "<br>");
}
else
{
document.write("It is a number...." + "<br>");
}
var week = 17;
if ( week < 1 || week > 7)
{
week = Number.NaN;
document.write(week);
}
//]]>
</script>
</body>
</html>

View the example in the browser

Supported Browser

Internet Explorer 7	Firefox 3.6	Google Chrome 7	Safari 5.0.1	Opera 10
Yes	Yes	Yes	Yes	Yes