用Node.js编写求圆的周长、面积、体积时单击计算出现没反应的情况,哪位能给出答案?
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>模块化编程</title>
</head>
<body>
请输入圆的半径:<input type="number" id="radius" name="radius">
<select id="type" name="type">
<option value="circu">周长</option>
<option value="area">面积</option>
<option value="volume">体积</option>
</select>
<input type="button"value="计 算" id="btnCal">
</body>
<script type="text/JavaScript">
var circle=(function(){
function getCircu(r){
return 2*Math.PI*r;
}
function getArea(r){
return Math.PI*Math.pow(r,2);
}
function getVolume(r){
return 4/3*Math.PI*Math.pow(r,3);
}
return {
getArea: getArea,
getCircu:getCircu,
getVolume:getVolume
}
})();
document.getElementById("btnCal").onclick=function(){
var r=parseFloat(document.getElementById("radius").value);
var type=ducument.getElementById("type").value;
var result;
switch (type){
case 'circu':
result=circle.getCircu(r);
break;
case 'area':
result=circle.getArea(r);
break;
case 'volume':
result=circle.getVolume(r);
break;
default:
result=0;
}
alert('计算结果为'+result.toFixed(2));
}
</script>
</html>