JS判断页面加载状态以及添加遮罩和缓冲动画的代码

function initialize() { 
addcloud(); //为页面添加遮罩 
document.onreadystatechange = subSomething; //监听加载状态改变 
} 
function addcloud() { 
var bodyWidth = document.documentElement.clientWidth; 
var bodyHeight = Math.max(document.documentElement.clientHeight, document.body.scrollHeight); 
var bgObj = document.createElement("div" ); 
bgObj.setAttribute( 'id', 'bgDiv' ); 
bgObj.style.position = "absolute"; 
bgObj.style.top = "0"; 
bgObj.style.background = "#000000"; 
bgObj.style.filter = "progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75" ; 
bgObj.style.opacity = "0.5"; 
bgObj.style.left = "0"; 
bgObj.style.width = bodyWidth + "px"; 
bgObj.style.height = bodyHeight + "px"; 
bgObj.style.zIndex = "10000"; //设置它的zindex属性，让这个div在z轴最大，用户点击页面任何东西都不会有反应| 
document.body.appendChild(bgObj); //添加遮罩 
var loadingObj = document.createElement("div"); 
loadingObj.setAttribute( 'id', 'loadingDiv' ); 
loadingObj.style.position = "absolute"; 
loadingObj.style.top = bodyHeight / 2 - 32 + "px"; 
loadingObj.style.left = bodyWidth / 2 + "px"; 
loadingObj.style.background = "url(../img/loading.gif)" ; 
loadingObj.style.width = "32px"; 
loadingObj.style.height = "32px"; 
loadingObj.style.zIndex = "10000"; 
document.body.appendChild(loadingObj); //添加loading动画- 
} 
function removecloud() { 
$( "#loadingDiv").remove(); 
$( "#bgDiv").remove(); 
} 
function subSomething() { 
if (document.readyState == "complete" ) //当页面加载完毕移除页面遮罩，移除loading动画- 
{ 
removecloud(); 
} 
}