css样式:
#export_page_cover {
display:none;
opacity: 0.7;
background-color:#FFF;
z-index: 1001;
position: fixed;
top: 0px;
bottom: 0px;
left: 0px;
right: 0px;
}
页面中显示一个div:<div id="export_page_cover"></div>
js文件中改变状态:$("#export_page_cover").css('display','none');