<div id="ajaxLoading" style="width: 100%;height: 100%;top: 0;left: 0;position: absolute;z-index: 9999;background:none repeat scroll 0 0 #CCCCCC;opacity: 0.4;filter:alpha(opacity=50)">Loading</div>
其中:
opacity: 0.4;filter:alpha(opacity=50)
opacity: 0.4 设置的是FireFox下面的透明效果;
filter:alpha(opacity=50) 设置的是IE下面的透明效果;