JavaScript - Math atan2 Method

Description

This method returns the arctangent of the quotient of its arguments. The atan2 method returns a numeric value between -pi and pi representing the angle theta of an (x, y) point.

Syntax

Its syntax is as follows −

Math.atan2( x, y ) ;

Parameter Details

x and y − Numbers.

Return Value

Returns the arctangent in radians of a number.

Math.atan2( ±0, -0 ) returns ±PI.
Math.atan2( ±0, +0 ) returns ±0.
Math.atan2( ±0, -x ) returns ±PI for x < 0.
Math.atan2( ±0, x ) returns ±0 for x > 0.
Math.atan2( y, ±0 ) returns -PI/2 for y > 0.
Math.atan2( ±y, -Infinity ) returns ±PI for finite y > 0.
Math.atan2( ±y, +Infinity ) returns ±0 for finite y > 0.
Math.atan2( ±Infinity, +x ) returns ±PI/2 for finite x.
Math.atan2( ±Infinity, -Infinity ) returns ±3*PI/4.
Math.atan2( ±Infinity, +Infinity ) returns ±PI/4.

Example

Try the following example program.

Live Demo

<html>   
   <head>
      <title>JavaScript Math atan2() Method</title>
   </head>
   
   <body>      
      <script type = "text/javascript">
         var value = Math.atan2(90,15);
         document.write("First Test Value : " + value ); 
         
         var value = Math.atan2(15,90);
         document.write("<br />Second Test Value : " + value ); 
         
         var value = Math.atan2(0, -0);
         document.write("<br />Third Test Value : " + value ); 
         
         var value = Math.atan2(+Infinity, -Infinity);
         document.write("<br />Fourth Test Value : " + value ); 
      </script>      
   </body>
</html>

Output

First Test Value : 1.4056476493802699
Second Test Value : 0.16514867741462683
Third Test Value : 3.141592653589793
Fourth Test Value : 2.356194490192345

javascript_math_object.htm