<style>
.test{    
  background:#000;    
  color:white;    
  width:200px;    
  position:absolute;    
  left:10px;    
  top:10px;    
   filter: Alpha(opacity=50);    
   -moz-opacity:.1;    
   opacity:0.1;    

} 
#apDiv3 {
 position:absolute;
 width:1280px;
 height:1024px;
 z-index:1;
 left: 0px;
 top: 0px;
}

</style>

<div id="apDiv3" class="test">
<input type="text" id="txt1" name="txt1" value="123456" />
</div>

document.getElementById("apDiv3").style.display="block";