Math.PI : PI « Math « JavaScript Tutorial

The PI property of the Math object is used to get the constant PI.

This is approximately 3.14159.

    <script language="JavaScript">
    function doMath(){
        var result = Math.PI;
        document.form1.answer.value = result;
    <form name=form1>
    The Approximate value of PI is:
    <input type="text" name="answer" size=20>
    <input type="button" value="Calculate" onClick='doMath()'>

9.19.2.The value of the constant PI: Math.PI
9.19.3.Use Math.PI to do calculation