来自数组的随机谷歌地图标记

我正在尝试从 Google Maps 上的数组中添加自定义标记我看到了另一个与此接近的问题，但提供的代码不允许 Google Maps API 选择标记图标

 function button1(location) {
var get1 = prompt ("Enter First Coord");
var get2 = prompt ("Enter Second Coord");

var icons = [
"https://raw.githubusercontent.com/Concept211/Google-Maps-Markers/master/images/marker_green.png",
"https://raw.githubusercontent.com/Concept211/Google-Maps-Markers/master/images/marker_purple.png",
"https://raw.githubusercontent.com/Concept211/Google-Maps-Markers/master/images/marker_orange.png",
"https://raw.githubusercontent.com/Concept211/Google-Maps-Markers/master/images/marker_white.png",
"https://raw.githubusercontent.com/Concept211/Google-Maps-Markers/master/images/marker_black.png",
"https://raw.githubusercontent.com/Concept211/Google-Maps-Markers/master/images/marker_blue.png"

];
var items;
var center = new google.maps.LatLng(get1,get2);
map.panTo(center);
var marker = new google.maps.Marker({
position: center,
map: map,

icon: items[Math.floor(Math.random()*icons .length)]
});

我不断收到“项目未定义”。如果我在代码上方定义它，我会在图标上收到一个不同的错误，提示“无法读取未定义的属性 '3'”： items[Math.floor(Math.random()*icons .length)] 代码

如果有人知道解决方案，我将不胜感激，谢谢！