//获取浏览器页面可见高度和宽度
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 = 50// _PageHeight > 61 ? (_PageHeight - 61) / 2 : 0,
  _LoadingLeft =50 //_PageWidth > 215 ? (_PageWidth - 215) / 2 : 0;

//加载gif地址
var Loadimagerul = "/Content/LoadJs/Image/loading.gif";

//在页面未加载完毕之前显示的loading Html自定义内容
var _LoadingHtml = '<div id="loadingDiv" style="position:absolute;left:0;width:100%;height:'
  + _PageHeight + 'px;top:0;background:#f3f8ff;opacity:1;filter:alpha(opacity=80);z-index:10000;"><div style="position: absolute; cursor1: wait; left: '
  + _LoadingLeft + 'px; top:' + _LoadingTop + 'px; width:300px;; height: 50px; line-height: 57px; padding-left: 50px; padding-right: 5px; background: #fff url('
  + Loadimagerul + ') no-repeat scroll 5px 12px; border: 0px solid #95B8E7; color: #696969; font-family:\'Microsoft YaHei\';">玩命加载中...</div></div>';

//呈现loading效果
document.write(_LoadingHtml);

//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);
  }
}