css3加载中蒙层

 

	var _PageHeight = document.documentElement.clientHeight,
	  _PageWidth = document.documentElement.clientWidth;
	//计算loading框距离顶部和左部的距离（loading框的宽度为215px，高度为61px）
	var _LoadingTop = _PageHeight > 61 ? (_PageHeight - 61) / 2 : 0,
	  _LoadingLeft = _PageWidth > 215 ? (_PageWidth - 215) / 2 : 0;
	//在页面未加载完毕之前显示的loading Html自定义内容
	var _LoadingHtml = '<div >页面加载中，请等待...</div></div>';
	//呈现loading效果
	document.write(_LoadingHtml);
	//window.onload = function () {
	//  var loadingMask = document.getElementById('loadingDiv');
	//  loadingMask.parentNode.removeChild(loadingMask);
	//};
	//监听加载状态改变
	document.onreadystatechange = completeLoading;
	//加载状态为complete时移除loading效果
	function completeLoading() {
	  if (document.readyState == "complete") {
	 var loadingMask = document.getElementById('loadingDiv');
	 loadingMask.parentNode.removeChild(loadingMask);
	  }
	}

.loading {
margin: .4rem;
text-align: center;
width: 100%;
}
.mask {
/*display: none; */
position: fixed;
top: 0%;
left: 0%;
width: 100%;
height: 100%;
background-color: black;
z-index:1001;
-moz-opacity: 0.7;
opacity:.70;
filter: alpha(opacity=70);
}