JavaScript atan() Method: Math Object


The atan() method of math object is used to get the arctangent (in radians) of a number.


Implemented in JavaScript 1.0




x:   A number

js math object atan method


In the following web document, atan() method returns the arctangent of various numbers.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<title>JavaScript Math object - atan() method example</title>
<h1 style="color: red">JavaScript Math object : atan() method</h1>
<hr />
<script type="text/javascript">
//This is done to make the following JavaScript code compatible to XHTML. <![CDATA[
document.write(Math.atan(0.50) + "<br />");
document.write(Math.atan(-0.50) + "<br />");
document.write(Math.atan(5) + "<br />");
document.write(Math.atan(10) + "<br />");
document.write(Math.atan(-5) + "<br />");

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

See also:

JavaScript Core objects, methods, properties.

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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";


includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv