제목이 맞게 됐는지 모르겠네요
제가 글 솜씨가 없어서
그냥 예제  보시면 이해 되실듯....

미리보기 : http://xscool.cafe24.com/bbs/zboard.php?id=story2&page=1&sn1=&divpage=1&sn=off&ss=on&sc=on&select_arrange=headnum&desc=asc&no=18

--------------------    아래가 소스 입니다    ------------------------


<script language="javascript">
function showPreview(pvObj)
{var wname = "preview";
  var wopt = "menubar=yes,scrollbars=yes,status=yes,resizable=yes,width=640,height=480";
  winResult = window.open("about:blank",wname,wopt);
  winResult.document.open("text/html", "replace");
  winResult.document.write(pvObj.value);
  winResult.document.close();
  return false;}
</script>

<table width="508" border="0" style="table-layout:fixed">
  <form name="previewform" onSubmit="return false">
  <tr><td width="502" height="420">
    <input type="button" class="button" value="미리보기" onClick="return showPreview(this.form.exsrc)" style="color:black; background-color:rgb(204,153,0);"><br>

    <textarea name="exsrc" class="entry" rows="25" style="border-color:rgb(204,153,0); border-style:solid; width:100%;" cols="68">

★이부분에 소스를 적어 줍니다.★


</textarea>
  </td></tr>
  </form>
</table>


--------------------    요기 까지    ------------------------