如果是纯文字内容的话可以不用管文档加载到哪里了就加载完成了;
如果div下面有图片的话(img标签就需要进行判断了)
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<div id="d">
<div id="loading">正在加载。。。</div>
<img src="https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1494214281262&di=ef0111cb95c5477f2dfc94acad9185dd&imgtype=0&src=http%3A%2F%2Fh5.86.cc%2Fwalls%2F20141217%2F1440x900_23b73a6904487a6.jpg">
<img src="https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1494214281262&di=d9369e8911c7ad7f74ca4427bdbfed51&imgtype=0&src=http%3A%2F%2Fpic10.nipic.com%2F20100929%2F4308872_150108084472_2.jpg">
<img src="https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1494214281262&di=87878630fa4786df3cdf8b09d8ec0d61&imgtype=0&src=http%3A%2F%2Ftupian.enterdesk.com%2F2013%2Fmxy%2F12%2F11%2F4%2F3.jpg">
</div>
<script type="text/javascript">
var div=document.getElementById("d")
function OnLoadElement(e){
var img= e.getElementsByTagName("img");
var num=0;
if(img.length<=0){
return 1;
}
for(var i=0;i<img.length;i++){
(function(j){
if(!img[j].complete){
img[j].onload=function(){
num++;
console.log("已经加载图片:"+num+"/"+img.length);
if(num==img.length){
document.getElementById("loading").style.display="none";
console.log("内容加载完成");
}
}
}else{
num++;
console.log("已经加载图片:"+num+"/"+img.length);
if(num==img.length){
document.getElementById("loading").style.display="none";
console.log("内容加载完成");
}
}
})(i);
}
}
OnLoadElement(div);
</script>
</body>
</html>