JavaScript Math.atan2()
Example - atan2(y,x)
Assume you had a point with the (x,y) coordinates of (4,8), you could calculate the angle in radians between that point and the positive X axis as follows:
Math.atan2(8, 4);
Definition and Usage
The Math.atan2() method returns the arctangent of the quotient of its arguments, as a numeric value between PI and -PI radians.
The number returned represents the counterclockwise angle in radians (not degrees) between the positive X axis and the point (x, y).
Note: With atan2(), the y coordinate is passed as the first argument and the x coordinate is passed as the second argument.
Browser Support
Math.atan2()
is an ECMAScript1 (ES1) feature.
ES1 (JavaScript 1997) is fully supported in all browsers:
Chrome | IE | Edge | Firefox | Safari | Opera |
Yes | Yes | Yes | Yes | Yes | Yes |
Syntax
Math.atan2(y, x)
Parameter | Description |
---|---|
y | Required. A number representing the y coordinate |
x | Required. A number representing the x coordinate |
Return Value
A number from PI to -PI. NaN if the value(s) is empty. |