Math.atan2() : atan2 « Math « JavaScript Tutorial

Syntax

math.atan2(num1, num2)

The atan2() method calculates the arctangent of the quotient of its parameters.

It returns a numeric value between -PI and PI representing the angle theta of an (x,y) point.

<html>
    <body>
    <script language="JavaScript">
    <!--
    function doMath(){
        var inputNum1=document.form1.input1.value;
        var inputNum2=document.form1.input2.value;
        var result = Math.atan2(inputNum1, inputNum2);
        document.form1.answer.value = result;
    }
    -->
    </script>
    <form name=form1>
    Enter First Number:
    <input type="text" name="input1" size=10>
    <br>
    Enter Second Number:
    <input type="Text" name="input2" size=10>
    <br><br>
    <input type="button" value="Calculate" onClick='doMath()'>
    <br>
    Answer:
    <input type="text" name="answer" size=10>
    </form>
    </body>
    </html>

9.6.atan2
	9.6.1.	Math.atan2()