div 테그

<div style="position:relative;">
  <div id="sub_title_option" style="position:absolute;z-index:+10;width:400px;height:400px;border:1px,solid;backgroundColor:blue;display:none">
           <table border='0' cellspacing='0' cellpadding='0' width='100%'>
             <select name="sub_title_no">
               <option value="">==선택==</option>
               <option value="1">수학의정석</option>
               <option value="2">영어완전정복</option>
             </select>
           </table>
           <table border="0" cellspacing="0" cellpadding="0">
             <tr>
               <td align="rignt"><input type="button" value="닫기" onClick="sub_title_option_view('');"></td>
             </tr>
           </table>
         </div>
         </div>


function sub_title_option_view(opt){
    alert(opt);
 if(opt>0){
  document.getElementById('sub_title_option').style.display=""; //보임
 }else{
  document.getElementById('sub_title_option').style.display="none"; //안보임
 }
}