#j2 {
      background-color: #000;           
      position: absolute; 
      z-index: 5;
       width:100%;
	   height:100%;
	   filter: alpha(opacity=55);
}


#f3 {     
        margin-top: 0px;       
        padding: 10px; 
      height: 400px; 
      position: absolute; 
      z-index: 10;

       left: 50%;
       width:500px;
       margin-left: -255px;   /* half the width + half the padding + single border */
}