วน loop รับค่าใน list ที่ไม่ตายตัวว่ามีเท่าไรยังไงครับ

function addField(area,field1,field2,limit)
{
	if (!document.getElementById) return; //Prevent older browsers from getting any further.
	var field_area = document.getElementById(area);
	var all_inputs = field_area.getElementsByTagName('input'); //Get all the input fields in the given area.
	//Find the count of the last element of the list. It will be in the format '<field><number>'. If the 
	//		field given in the argument is 'friend_' the last id will be 'friend_4'.
	var last_item = all_inputs.length - 1;
	var last = all_inputs[last_item].id;
	var count = Number(last.split("_")[1]) + 1;
	
	if (count > limit && limit > 0) return;
	field_area.innerHTML += "<li><?=$text_add?><input name='"+(field1+count)+"' id='"+(field1+count)+"' type='<?=$type_input?>' />&nbsp; CIName ใหม่<input name='"+(field2+count)+"' id='"+(field2+count)+"' type='text' /> <a style=\"cursor:pointer;color:blue;\" onclick=\"this.parentNode.parentNode.removeChild(this.parentNode);\">Remove Field</a></li>";
}

<form id="New_Butt_Frm" name="New_Butt_Frm" method="post" action="cimanage.php?mod=new&aaa=true">
	<input type="submit" name="New_Butt" id="New_Butt" value="New" />
</form>
<form id="Old_Butt_Frm" name="Old_Butt_Frm" method="post" action="cimanage.php?mod=replace&aaa=true">
	<input type="submit" name="Replace_Butt" id="Replace_Butt" value="Replace" />
</form>
<?php
	include "connect.php";
	$str = "SELECT * 
					FROM tb_Purchase 
					WHERE ID_Purchase = ".$_SESSION['ID_Purchase']."";
	$conn->open($sql);
	$rs = $conn->execute($str);
	$amount = $rs->Fields['Acc_Amount']->Value;
	$rs->Close();
	$conn->Close();
?>
<p>เช่าทั้งหมด <?=$amount?> เครื่อง</p>
<?php
if ($_GET['aaa'] == "true")
{
?>
	<form name="frm" method="post" action="cimanage.php?submit_save1=Save">
	<strong>CIName</strong><br />
	<ol id="CIName">
	<li><?=$text_add?><input type=<?=$type_input?> name="CIOld_1" id="CIOld_1" />&nbsp; CIName ใหม่<input type="text" name="CINew_1" id="CINew_1" /></li>
	</ol>
	<input id="add_ci" name="add_ci" type="button" value="+" onclick="addField('CIName','CIOld_','CINew_',<?=$amount?>);" />
	<br /><br />
	<input type="submit" name="submit_save" id="submit_save" value="Save" />
	</form>
<?php
}
?>