จะแก้ไขข้อมูลจังหวัด select ไม่เป็นครับ รบกวนดูให้หน่อยครับ

$(function(){
   $("txt14").blur(function(){
       var pid = $(this).val();
       $("#selProvince2 option[value='"+pid+"']").attr("selected",true);
   });
   var defaultOption = '<option value=""> ------- เลือก ------ </option>';
...
......
........

<script src="<?php echo $jqLib; ?>"></script>
<script type="text/javascript">
 // Specify a function to execute when the DOM is fully loaded.
$(function(){
       $("txt14").blur(function(){
           var pid = $(this).val();
           $("#selProvince2 option[value='"+pid+"']").attr("selected",true);
       });
	var defaultOption = '<option value=""> ------- เลือก ------ </option>';
	var loadingImage  = '<img src="img/loading4.gif" alt="loading" />';
	// Bind an event handler to the "change" JavaScript event, or trigger that event on an element.
	$('#selProvince').change(function() {
		$("#selAmphur").html(defaultOption);
		$("#selTumbon").html(defaultOption);
		// Perform an asynchronous HTTP (Ajax) request.
		$.ajax({
			// A string containing the URL to which the request is sent.
			url: "jsonAction.php",
			// Data to be sent to the server.
			data: ({ nextList : 'amphur', provinceID: $('#selProvince').val() }),
			// The type of data that you're expecting back from the server.
			dataType: "json",
			// beforeSend is called before the request is sent
			beforeSend: function() {
				$("#waitAmphur").html(loadingImage);
			},
			// success is called if the request succeeds.
			success: function(json){
				$("#waitAmphur").html("");
				// Iterate over a jQuery object, executing a function for each matched element.
				$.each(json, function(index, value) {
					// Insert content, specified by the parameter, to the end of each element
					// in the set of matched elements.
					 $("#selAmphur").append('<option value="' + value.AMPHUR_ID + 
											'">' + value.AMPHUR_NAME + '</option>');
				});
			}
		});
	});
	
	$('#selAmphur').change(function() {
		$("#selTumbon").html(defaultOption);
		$.ajax({
			url: "jsonAction.php",
			data: ({ nextList : 'tumbon', amphurID: $('#selAmphur').val() }),
			dataType: "json",
			beforeSend: function() {
				$("#waitTumbon").html(loadingImage);
			},
			success: function(json){
				$("#waitTumbon").html("");
				$.each(json, function(index, value) {
					 $("#selTumbon").append('<option value="' + value.DISTRICT_ID + 
											'">' + value.DISTRICT_NAME + '</option>');
				});
			}
		});
	});
});

</script>

<script src="<?php echo $jqLib; ?>"></script>
<script type="text/javascript">
 // Specify a function to execute when the DOM is fully loaded.
$(function(){
	$("txt14").blur(function(){
		var pid = $(this).val();
		$("#selProvince2 option[value='"+pid+"']").attr("selected",true);
	});
		var defaultOption = '<option value=""> ------- เลือก ------ </option>';
	var loadingImage  = '<img src="img/loading4.gif" alt="loading" />';

	// Bind an event handler to the "change" JavaScript event, or trigger that event on an element.
	$('#selProvince').change( province_change(''));
	$('#selAmphur').change( amphur_change() );
});

function province_change(default) {
	$("#selAmphur").html(defaultOption);
	$("#selTumbon").html(defaultOption);
	// Perform an asynchronous HTTP (Ajax) request.
	$.ajax({
		// A string containing the URL to which the request is sent.
		url: "jsonAction.php",
		// Data to be sent to the server.
		data: ({ nextList : 'amphur', provinceID: $('#selProvince').val() }),
		// The type of data that you're expecting back from the server.
		dataType: "json",
		// beforeSend is called before the request is sent
		beforeSend: function() {
			$("#waitAmphur").html(loadingImage);
		},
		// success is called if the request succeeds.
		success: function(json){
			$("#waitAmphur").html("");
			// Iterate over a jQuery object, executing a function for each matched element.
			$.each(json, function(index, value) {
				// Insert content, specified by the parameter, to the end of each element
				// in the set of matched elements.
				 $("#selAmphur").append(
					'<option value="' + value.AMPHUR_ID + '" '+ 
					(default>''? " selected " : "")+
					' >' + value.AMPHUR_NAME + '</option>');
			});
		}
	});
}

function amphur_change(default) {
	$("#selTumbon").html(defaultOption);
	$.ajax({
		url: "jsonAction.php",
		data: ({ nextList : 'tumbon', amphurID: $('#selAmphur').val() }),
		dataType: "json",
		beforeSend: function() {
			$("#waitTumbon").html(loadingImage);
		},
		success: function(json){
			$("#waitTumbon").html("");
			$.each(json, function(index, value) {
				 $("#selTumbon").append(
					'<option value="' + value.DISTRICT_ID + '" '+
					(default>''? " selected " : "")+
					' >' + value.DISTRICT_NAME + '</option>');
			});
		}
	});
}

province_change( 'amphur_default' );  // บันทัดนี้ถูกเพิ่มเข้ามา เพื่อเรียกใช้งาน event province_change 
// เพราะตอนสร้าง html มันถูกกำหนดชื่อไว้ก่อน เลยไม่มี event change ส่งค่าไปเปลี่ยน อำเภอ
// เมื่อ list อำเภอถูกสร้างแล้ว จำเป็นต้องมี ค่า default ของอำเภอส่งไป้วย 

// ในทำนองเดียวกัน ถ้ามีกำหนด tumbon ก็ต้องมี event amphur_change
amphur_change('tumbol_default'); // ใส่ค่า tumbol ที่ถูกเรียกไว้ด้วย
</script>