loading 加载提示 ······ 透明遮罩 居中 代码如下: body{ margin: 0; font-size: 12px; line-height: 100%; font-family: Arial, sans-serif; } .background { display: block; width: 100%; height: 100%; opacity: 0.4; filter: alpha(opacity=40); background:while; position: absolute; top: 0; left: 0; z-index: 2000; } .pro