javascript - How to add a mask div to cortona3d viewer in chrome? -

cortona3d viewer 3d product www.cortona3d.com, want show mask div before cortona3d viewer, aaa div not show on front end in code below

<div style="position:absolute;top:0;left:0;width:500px;height:300px">     <div class="bbb" style="position: absolute;width:100%;height:100%;transform:translate3d(0, 0, 0); ">       <embed  src="aeronaval_assemble.wrl" width="100%" height="100%" type="application/x-cortona" pluginspage="http://www.cortona3d.com/cortona" vrml_splashscreen="false" vrml_dashboard="false" vrml_background_color="#cdcdcd" contextmenu="false" >           </div>     <div class="aaa" style="position: absolute;width:100%;height:100%;background:blue;transform:translate3d(0, 0, 100px); "></div> </div>