js处理多个上传

<script language="JavaScript">
var num=1;
function show(obj){
if(obj.checked){
document.all.photoyn.style.display="";
document.all.photoyn.innerHTML="<input type=\"file\" size=\"25\" name=\"photopath\" class=\"upfile\">
<font color=\"red\">（只允许700K以内的GIF或JPG图片）</font>
<table id=\"TB\" width=\"100%\" height=\"0px\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\">
<tr><td></td></tr>
</table>
<input type=\"button\" value=\"添加\"title=\"增加一个上传\" onclick=\"oRow=TB.insertRow();oCell=oRow.insertCell();oCell.innerHTML='<input type=file size=25 name=photopath'+Number(num)+' class=upfile>';numnum=num+1\">  
<input type=\"button\" value=\"删除\" title=\"去掉一个上传\" onclick=\"oCell=TB.deleteRow()\">";
}else{
document.all.photoyn.innerHTML="";
document.all.photoyn.style.display="none";
}
}
</script>

是否上传照片？<input type="checkbox" name="nfile" id="nfile" onclick="show(this)">
<div id="photoyn" style="display:none;padding:2px 0 5px 0"></div>