Javascript 无法读取属性'；长度'；wheelnav.createWhee处未定义的

我对Wheelnav.js有一些问题 当我在html文件中包含脚本时，chrome显示以下错误：

未捕获的TypeError:无法读取未定义的属性“length” 在wheelnav.createWheel（wheelnav.js:271） 在window.onload（script.js:14）

这是我的剧本：

window.onload = function() {
var wheel = new wheelnav("wheelDiv");

wheel = new wheelnav("wheelDiv");
wheel.wheelRadius = 130;
wheel.maxPercent = 1.2;
wheel.colors = colorpalette.oceanfive;
wheel.clickModeRotate = false;
wheel.slicePathFunction = slicePath().WheelSlice;
wheel.navAngle = 30;
wheel.createWheel(["basic", "hover", "select", null, null, null]);

wheel = new wheelnav("wheelDiv");
wheel.sliceHoverTransformFunction = 
sliceTransform().RotateTitleTransform;
wheel.sliceSelectedTransformFunction = 
sliceTransform().MoveMiddleTransform;
wheel.wheelRadius = wheel.wheelRadius * 0.8;
wheel.colors = colorpalette.fractallove;

wheel.createWheel(["Thank you", "for", "download", "hello"]);
wheel.navigateWheel(2);

var piemenu = new wheelnav("piemenu");
piemenu.wheelRadius = piemenu.wheelRadius * 0.83;
piemenu.createWheel();
};

---

似乎您没有具有相应id的div

var piemenu = new wheelnav("piemenu");

它要求：

<div id="piemenu"></div>