JScript ユーザーズ ガイド、オブジェクトの作成にプロトタイプを使う

まんま

function Circle(xPoint, yPoint, radius) {
  this.x = xPoint;
  this.y = yPoint;
  this.r = radius;
}
var aCircle = new Circle(5, 11, 99);

Circle.prototype.pi = Math.PI;

function ACirclesArea () {
  return this.pi * this.r * this.r;
}
Circle.prototype.area = ACirclesArea;
WScript.Echo(aCircle.area());

「var a = ACircle.area();」は「var a = aCircle.area();」の間違いか？？？

まんま

String.prototype.trim = function()
{
  return this.replace(/(^\s*)|(\s*$)/g, "");
}

var s = "    前後にスペースがあります    ";

WScript.Echo(s + " (" + s.length + ")");

s = s.trim();
WScript.Echo(s + " (" + s.length + ")");