ส่งค่าให้กับฟังก์ชั่นแสดงจังหวัด อำเภอ ตำบล เป็น Select/Listmenu

<?php
echo '<span id="provinceDiv">';
	echo "<label for=\"province\"></label><select name=\"province\" id=\"province\" onchage=\"dochange('province')\">\n";
	echo "<option value=\"$province\">กรุณาเลือกจังหวัด</option> \n" ;
	echo "</select></span>\n"; 
?>

function dochange( obj )
{
	var req = Inint_AJAX();
	var province = document.getElementById( 'province' ).value;
	var tumbon = document.getElementById( 'tumbon' ).value;
	if ( obj && obj.name == 'province' ) //àÁ×èÍ·Ó¡ÒÃàÅ×Í·Õè¨Ñ§ËÇÑ´ÁÒ ãËéà¤ÅÕÂÃì¤èÒÍÓàÀÍ
	{
		var amphur = "";
	}
	else //àÅ×Í¡ÃÒ¡ÒÃÍ×è¹
	{
		var amphur = document.getElementById( 'amphur' ).value;
	};
	var data = "province=" + province + "&amphur=" + amphur + "&tumbon=" + tumbon;
	req.onreadystatechange = function()
	{
		if ( req.readyState == 4 )
		{
			if ( req.status == 200 )
			{
				var datas = eval( '(' + req.responseText + ')' ); // JSON
				
				document.getElementById( 'provinceDiv' ).innerHTML = datas[0].province;
				document.getElementById( 'amphurDiv' ).innerHTML = datas[0].amphur;
				document.getElementById( 'tumbonDiv' ).innerHTML = datas[0].tumbon;
			};
		};
	};
	req.open( "post" , "../function/province.php" , true ); //ÊÃéÒ§ connection
	req.setRequestHeader( "Content-Type", "application/x-www-form-urlencoded" ); // set Header
	req.send( data ); //Ê觤èÒ
};

<?
	header( "Cache-Control: no-cache, must-revalidate" );
	header( "Pragma: no-cache" );
	header( "content-type: application/x-javascript; charset=windows-874" );

	$province = $_POST[province];
	$amphur = $_POST[amphur];
	$tumbon = $_POST[tumbon];
	
	
	require("../connect/pconnect.php");
	$sql = "SELECT ProvinceID, ProvinceName FROM province";
	$result = mysql_query( $sql );
	echo "[{\"province\":\"";
	echo "<label for='province'></label>";
	echo "<select name='province' id='province' onchange='dochange(this)'>";
	echo "<option value='0'>--¡ÃسÒàÅ×Í¡¨Ñ§ËÇÑ´--</option>";
	while( $fetcharr = mysql_fetch_array( $result ) )
	{ 
		$id = $fetcharr[ProvinceID];
		$name = $fetcharr[ProvinceName];
		echo "<option value='$id'";
		if ( $province == $id ) //àÅ×Í¡¨Ñ§ËÇÑ´·ÕèàÅ×Í¡äÇé
		{
			echo " selected='selected'";
		};
		echo ">$name</option>";
	};
	echo "</select>\",\"amphur\":\"";

	echo "<label for='amphur'></label>";
	echo "<select name='amphur' id='amphur' onchange='dochange(this)'>";
	//¶éÒÁÕ¡ÒÃàÅ×Í¡¨Ñ§ËÇÑ´ÁÒáÅéÇãËéáÊ´§ÍÓàÀ͵èÍ
	if ( $province != "0" && $province != "" )
	{
		echo "<option value='0'>--¡ÃسÒàÅ×Í¡ÍÓàÀÍ--</option>";
		$sql = "SELECT AmphurID, AmphurName FROM amphur WHERE ProvinceID='$province'";
		$result = mysql_query( $sql );
		while( $fetcharr = mysql_fetch_array( $result ) )
		{
			$id = $fetcharr[AmphurID];
			$name = $fetcharr[AmphurName];
			echo "<option value='$id'";
			if ( $amphur == $id ) //àÅ×Í¡ÍÓàÀÍ·ÕèàÅ×Í¡äÇé
			{
				echo " selected='selected'";
			};
			echo ">$name</option>";
		};
	}
	else
	{
		echo "<option value=''>--------------</option>";
	};

	echo "</select>\",\"tumbon\":\"";

	echo "<label for='tumbon'></label>";
	echo "<select name='tumbon' id='tumbon'>";

	//¶éÒÁÕ¡ÒÃàÅ×Í¡ÍÓàÀÍÁÒáÅéÇãËéáÊ´§µÓºÅµèÍ
	if ( $amphur != "0" && $amphur != "" )
	{
		echo "<option value='0'>--¡ÃسÒàÅ×Í¡µÓºÅ--</option>";
		$sql = "SELECT TumbonID, TumbonName FROM tumbon WHERE amphurID=$amphur";
		$result = mysql_query( $sql );
		while( $fetcharr = mysql_fetch_array( $result ) )
		{
			$id = $fetcharr[TumbonID];
			$name = $fetcharr[TumbonName];
			echo "<option value='$id'";
			if ( $tumbon == $id ) //àÅ×Í¡µÓºÅ·ÕèàÅ×Í¡äÇé
			{
				echo " selected='selected'";
			};
			echo ">$name</option>";
		};
	}
	else
	{
		echo "<option value=''>--------------</option>";
	};
	echo "</select>\"}]";

	mysql_close();
?>