.chemidexlightbox{ color:#333; display:none; position:absolute; top:25%; left:25%; border:1px solid #000; background-color:white; z-index:2001; overflow:hidden; } #chemidexoverlay{ display:none; position:absolute; top:0; left:0; width:100%; height:100%; z-index:1000; background-color:#333; -moz-opacity:0.8; opacity:.80; filter:alpha(opacity=80); } .chemidexlightbox[id]{ position:fixed; }#chemidexoverlay[id]{ position:fixed; }