กดปุ่มแล้วเพิ่ม textbox แต่พอวน loop แล้วกดปุ่มมันไม่สามารถเพิ่มได้ครับ

<script language="javascript">
	function CreateNewRow(a)
	{


for(x=1;x<=a;x++){
		var intLine = parseInt(document.frmMain["hdnMaxLine"+x].value);
		intLine++;

alert (["hdnMaxLine"+x]);

		var theTable = document.all["tbExp"+x]
		var newRow = theTable.insertRow(theTable.rows.length)
		newRow.id = newRow.uniqueID

		var item1 = 1
		var newCell

		//*** Column 1 ***//
		newCell = newRow.insertCell(0)
		newCell.id = newCell.uniqueID
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<center><INPUT TYPE=\"TEXT\" SIZE=\"20\" NAME=\"Column1_"+intLine+"\" VALUE=\"\"></center>"

		document.frmMain["hdnMaxLine"+a].value = intLine;
        
        }
	}

</script>




<?php

include "includes/connect.inc.php";


	echo <<<HTMLBLOCK
        <table width="100%" align="center" border="0" class="style6">
        <tr><td align="center" valign="top">
<br>
<table width="100%" border="1" cellpadding="0" cellspacing="0">
	<tr align="center" height="30" class="style2">
    <td width='5%' background="icon/sub_h_menu.png">Code Site</td>
    <td width='30%' background="icon/sub_h_menu.png">Name Site</td>
    <td width='15%' background="icon/sub_h_menu.png">Mail</td>
    </tr>
HTMLBLOCK;

$sql = "SELECT top 3 Des COLLATE Thai_CI_AS as myname,* FROM [SiteInformation] order by [No_] asc";
$result = mssql_query($sql) or die ("MSSQL upit nije uspio!!!");

    $a=0;
while($row = mssql_fetch_array($result)){
    if($a%2==0){
        $color="#E8E8E8";
    }else{
        $color="#FFFFFF";
    }
$a++;

$Des =iconv("TIS-620","UTF-8",$row["myname"]);

    echo "<tr bgcolor='$color' class='style3'>";
    echo "<td align='center'>$row[No_]</td>";
    echo "<td align='left'>&nbsp;&nbsp;&nbsp;$Des</td>";
    echo "<td align='left'>";
?>


<form name="frmMain" method="post">
<table width="100%" border="0" id="tbExp<?=$a; ?>">
  <tr>
  </tr>
</table>
<input type="hidden" name="hdnMaxLine<?=$a; ?>" value="0">
<input name="btnAdd" type="button" id="btnAdd" value="+" onClick="CreateNewRow(<?=$a; ?>);">
<input name="btnDel" type="button" id="btnDel" value="-" onClick="RemoveRow(<?=$a; ?>);">
</form>

<?php
    echo "</td>";
    echo "</tr>";

}




	echo <<<HTMLBLOCK
</table>

      </td></tr>
      </table>
HTMLBLOCK;