[JS] Over Layer

<script type="text/javascript">
 function view(opt) {
  if(opt) {
   spec1.style.display = "block";
  }
  else {
   spec1.style.display = "none";
  }
 }
</script>

<div style="position:relative;">
 <a href="#" onmouseover="view(true)">버튼</a>
  <div id="spec1"  style="display:none; position:absolute; top:20px; left:20px;">
  레이어
  <a href="" onmousedown="view(false)" >닫힘</a>
  </div>
</div>