This method returns the arc tangent of the quotient of its argument. The ATAN2 method returns the numerical value between -pi and PI compared to the angle theta at (x,y) point.
Grammar
Math.atan2( x, y ) ;
Here are the details of the parameters:
Return value:
Returns the arctangent of a number in radians
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:
<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>
This will produce the following results:
First Test Value : 1.4056476493802698 Second Test Value : 0.16514867741462683 Third Test Value : 3.141592653589793 Fourth Test Value : 2.356194490192345
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