<script> var round; var area; var PI = 3.14; function getArea() { round = parseFloat(document.getElementById("round").value); area = 4/3*PI*round*round; setArea(area); } function setArea(area) { document.getElementById("area").innerHTML = "The Round's Area is : "+area ; } </script>
echo "<input type='text' id='round' value=''/>";
echo "<input type='button' id='submit' value='Submit' onclick='javascript:getArea()'>";
echo "<p id='area'></p>";
?>
<script>
var round;
var area;
var PI = 3.14;
function getArea()
{
round = parseFloat(document.getElementById("round").value);
area = 4/3*PI*round*round;
setArea(area);
}
function setArea(area)
{
document.getElementById("area").innerHTML = "The Round's Area is : "+area ;
}
</script>