js實現的頁面加載完畢之前loading提示效果完整示例

//獲取瀏覽器頁面可見高度和寬度

var _PageHeight = document.documentElement.clientHeight,

   _PageWidth = document.documentElement.clientWidth;

//計算loading框距離頂部和左部的距離（loading框的寬度為215px，高度為61px）

var _LoadingTop = _PageHeight > 61 ? (_PageHeight - 61) / 2 : 0,

   _LoadingLeft = _PageWidth > 215 ? (_PageWidth - 215) / 2 : 0;

//在頁面未加載完畢之前顯示的loading Html自定義內容

var _LoadingHtml = '<div id="loadingDiv" style="position:absolute;left:0;width:100%;height:' + _PageHeight + 'px;top:0;background:#f3f8ff;opacity:0.8;filter:alpha(opacity=80);z-index:10000;"><div style="position: absolute; cursor1: wait; left: ' + _LoadingLeft + 'px; top:' + _LoadingTop + 'px; width: auto; height: 57px; line-height: 57px; padding-left: 50px; padding-right: 5px; background: #fff url(/Content/loading.gif) no-repeat scroll 5px 10px; border: 2px solid #95B8E7; color: #696969; font-family:\'Microsoft YaHei\';">頁面加載中，請等待...</div></div>' ;

//呈現loading效果

document.write(_LoadingHtml);

//window.onload = function () {

//  var loadingMask = document.getElementById('loadingDiv');

//  loadingMask.parentNode.removeChild(loadingMask);

//};

//監聽加載狀態改變

document.onreadystatechange = completeLoading;

//加載狀態為complete時移除loading效果

function completeLoading() {

   if (document.readyState == "complete" ) {

  var loadingMask = document.getElementById( 'loadingDiv' );

  loadingMask.parentNode.removeChild(loadingMask);

   }

}