มีวิธีนำค่าจาก textbox ออกมาเป็นตัวแปรได้หรือไม่ คือผมรับค่า json ผ่าน ajax มาเป็น $("#txtAmphur").val(result.District1);

	var txtField = ['txtProvince','txtAmphur','txtDistrict']
	txtField.forEach(function(entry){
		$( "#"+entry).autocomplete({
		  minLength: 0,
			source: "proc/autocomplete.php?action="+$( "#"+entry).data('action')+'&province='+$('#txtProvince_id').val()+'&amphur='+$('#txtAmphur_id').val(),
			select: function( event, ui ) {
					if($('#'+$(this).attr('id')+'_id').val() != ui.item.id && $(this).attr('id') == 'txtProvince' ){
						$('#frmLandmark input[name*="txtAmphur"]').val('');
						$('#frmLandmark input[name*="txtDistrict"]').val('');
						$('#txtPostalCode').val('');
					}else if($('#'+$(this).attr('id')+'_id').val() != ui.item.id && $(this).attr('id') == 'txtAmphur' ){
						$('#frmLandmark input[name*="txtDistrict"]').val('');
						$('#txtPostalCode').val('');
					}else if($('#'+$(this).attr('id')+'_id').val() != ui.item.id && $(this).attr('id') == 'txtDistrict' ){
						$('#txtPostalCode').val(ui.item.zipcode)
					}
					$('#'+entry+'_id').val(ui.item.id);
			}
		}).focus(function(){
				  $(this).data("uiAutocomplete").option('source',"proc/autocomplete.php?action="+$( "#"+entry).data('action')+'&province='+$('#txtProvince_id').val()+'&amphur='+$('#txtAmphur_id').val());
				  $(this).data("uiAutocomplete").search($(this).val());
		})
		
	});

<tr>
	<td align="right">Province : </td>
	<td>
        <input type="hidden" style="width:220px;margin-left:2px;" size="30" value="<?php echo $rs[''] ?>" id="txtProvince_id" name="txtProvince_id" />
        <input type="text" style="width:220px;margin-left:2px;" size="30" data-action="getProvince" value="<?php echo $rs['name'] ?>" id="txtProvince" name="txtProvince" />	
    </td>
</tr>
<tr>
	<td align="right">Amphur : </td>
	<td>
        <input type="hidden" style="width:220px;margin-left:2px;" size="30" value="<?php echo $rs[''] ?>" id="txtAmphur_id" name="txtAmphur_id" />	
        <input type="text" style="width:220px;margin-left:2px;" size="30" data-action="getAmphur" value="<?php echo $rs[''] ?>" id="txtAmphur" name="txtAmphur" />	
    </td>
</tr>
<tr>
	<td align="right">District : </td>
	<td>
        <input type="hidden" style="width:220px;margin-left:2px;" size="30" value="<?php echo $rs[''] ?>" id="txtDistrict_id" name="txtDistrict_id" />
        <input type="text" style="width:220px;margin-left:2px;" size="30" data-action="getDistrict" value="<?php echo $rs[''] ?>" id="txtDistrict" name="txtDistrict" />
    </td>
</tr>
<tr>
	<td align="right">PostalCode :</td>
	<td>
	<input type="text" size="30"  value="<?php echo $rs['postalcode'] ?>" id="txtPostalCode" name="txtPostalCode" />	</td>
</tr>

		case 'getProvince':
			$sql= " 
			select province_id as id  ,province_name as value
			from mt_province where province_name like '%".$app->chkSql($_REQUEST['term'])."%' or province_code = '".$app->chkSql($_REQUEST['term'])."'   limit 20 ";
			$query = $db->query($sql);
			$json = '[';
			while($rs = $db->fetch_array($query)){
				$json .= json_encode($rs).',';
			}
			echo  substr($json,0,-1).']';
		break;	

		case 'getAmphur':
			$sql= " 
			select amphur_id as id  ,amphur_name as value
			from mt_amphur where amphur_name like '%".$app->chkSql($_REQUEST['term'])."%' and province_id = '".$app->chkSql($_REQUEST['province'])."'  limit 20 ";
			$query = $db->query($sql);
			$json = '[';
			while($rs = $db->fetch_array($query)){
				$json .= json_encode($rs).',';
			}
			echo  substr($json,0,-1).']';
		break;	
		
		case 'getDistrict':
			$sql= " 
			select district_id as id  ,district_name as value,b.zipcode 
			from mt_district a  
			inner join mt_zipcodes b on b.district_code = a.district_code 
			 where district_name like '%".$app->chkSql($_REQUEST['term'])."%' and amphur_id = '".$app->chkSql($_REQUEST['amphur'])."'  limit 20 ";
			$query = $db->query($sql);
			$json = '[';
			while($rs = $db->fetch_array($query)){
				$json .= json_encode($rs).',';
			}
			echo  substr($json,0,-1).']';
		break;