engine_loader_v3.js这个js来自哪里，页面加载时会出现这个错误
“错误: 无法获取未定义或 null 引用的属性“appendChild”，f12发现源码

InsertDiv: function() {
var d = document.getElementsByTagName('body')[0];
var j = document.createElement('div');
j.setAttribute('id', this.conf.strDaohangDivId);
// j.style.cssText = "position: fixed; z-index: 350000000; right: 0px; width: 255px; height: 365px; bottom: 59px; display: block;";
j.style.cssText = "position: fixed; z-index: 2147483640; right: 0px; width: 0px; height: 0px; bottom: 59px; display: block;";
if (!document.getElementById(this.conf.strDaohangDivId)) {
d.appendChild(j);
}
},
获取到的 d为null