กด Submit Form แล้วพอ Back ย้อนกลับ มันขึ้นเตือนว่า "ยืนยันการส่งแบบฟอร์มอีกครั้ง" แก้ไงดีครับ

<?php
ob_start();
session_start();
$rname = $_GET["name"];
$rid = $_GET["id"];
$pagecurrent = "รายละเอียดห้องพัก " . $rname . " | ";
include ("header.php");
?>
<?php
include ("config.php");
?>
<script language="JavaScript">
	function submitform() {
		if (confirm('คุณแน่ใจที่จะจองหรือไม่') != true) {
			return false;

		} else {
			return true;
		}
	}
</script>
<?php
if ($_GET['stat'] == "check") {
	mysql_query("SET NAMES UTF8");
	$sql = "select * from room where r_id=$rid";
	$mydata = mysql_query($sql);
	$row = mysql_fetch_array($mydata);
	$picture = $row["r_pic"];
	$price = $row["r_price"];
	$detail = $row["r_detail"];
	$rtype = $row["r_type"];
	if (empty($_POST["date"]) || empty($_POST["date2"])) {
		$datenow = $_SESSION["datenow"];
		$dat = explode('/', $datenow);
		$datenow1 = $dat[2] . '-' . $dat[1] . '-' . $dat[0];
		$datecho = $dat[0] + 1 . "/" . $dat[1] . "/" . $dat[2];
	} else {
		$datenow = $_POST["date"];
		$datecho = $_POST["date2"];
	}
	//$datenow = $_SESSION["datenow"];

	$showdatenum = "none";
	$chosech = '';
	$logform = '';
	$showde = 'none';
	$review = "none";
	if ($_COOKIE["cstatus"] == "user") {
		$logform = 'none';
		$review = "";
	}
	if (trim($_REQUEST['date']) != "" and trim($_REQUEST['date2']) != "") {
		$datechin = $_REQUEST['date'];
		$datechou = $_REQUEST['date2'];
		$ardatechin = explode("/", $datechin);
		$datechin1 = $ardatechin[2] . '-' . $ardatechin[1] . '-' . $ardatechin[0];
		$_SESSION["datere"]= $datechin1;
		$ardatechou = explode("/", $datechou);
		$datechou1 = $ardatechou[2] . '-' . $ardatechou[1] . '-' . $ardatechou[0];
		mysql_query("SET NAMES UTF8");
		$sqlcheck = "select * from booking where bookchin >= '$datechin1' and bookchout >= '$datechou1' and bookrid = $rid and bookstatus < 4";
		$mydatacheck = mysql_query($sqlcheck);
		$rowcheck = mysql_fetch_array($mydatacheck);
		if ($rowcheck) {
			echo "<script>alert('วันที่ ที่คุณได้เลือกไม่ว่าง คุณสามารค้นหาวันที่จองได้หน้าเว็บไซต์');</script>";
			echo "<meta http-equiv='refresh' content='0;URL=index.php'>";
		} else {
			if ($_SESSION["cstatus2"] == "user") {
				$showde = '';
				$logform = 'none';
				$showdatenum = "";
				$chosech = 'none';
				$review = "";
				$datchin = explode('/', $datechin);
				$datchou = explode('/', $datechou);
				$datecheckout = $datchou[2] . '-' . $datchou[1] . '-' . $datchou[0];
				$datecheckin = $datchin[2] . '-' . $datchin[1] . '-' . $datchin[0];
				$allday = (strtotime($datecheckout) - strtotime($datecheckin)) / (60 * 60 * 24);
				$dayyy = $allday + 1;
				$money = $price * $allday;
			} else {
				$showdatenum = "";
				$chosech = 'none';
				$review = "none";
				$datchin = explode('/', $datechin);
				$datchou = explode('/', $datechou);
				$datecheckout = $datchou[2] . '-' . $datchou[1] . '-' . $datchou[0];
				$datecheckin = $datchin[2] . '-' . $datchin[1] . '-' . $datchin[0];
				$allday = (strtotime($datecheckout) - strtotime($datecheckin)) / (60 * 60 * 24);
				$dayyy = $allday + 1;
				$money = $price * $allday;
			}
		}
		if ($datechin1 < $datenow1) {
			echo '<script>alert("คุณเลือกวัน Check In ไม่ถูกต้อง");return false;</script>';
			$showdatenum = "none";
			$chosech = '';
			$showde = 'none';
		}
		if ($datechou1 <= $datechin1) {
			echo '<script>alert("คุณเลือกวัน Check Out ไม่ถูกต้อง");return false;</script>';
			$showdatenum = "none";
			$chosech = '';
			$showde = 'none';
		}

	}
} else {
	mysql_query("SET NAMES UTF8");
	$sql = "select * from room where r_id=$rid";
	$mydata = mysql_query($sql);
	$row = mysql_fetch_array($mydata);
	$picture = $row["r_pic"];
	$price = $row["r_price"];
	$detail = $row["r_detail"];
	$rtype = $row["r_type"];
	$review = "none";
	if (!empty($_SESSION["daycheckin"][0])) {
		$datenow = $_SESSION["daycheckin"][0];
		$datecho = $_SESSION["daycheckout"][0];
	} else {
		$datenow = $_SESSION["datenow"];
		$dat = explode('/', $datenow);
		$datecho = $dat[0] + 1 . "/" . $dat[1] . "/" . $dat[2];
	}

	$showdatenum = "none";
	$chosech = '';
	$logform = '';
	$showde = 'none';
	if ($_COOKIE["cstatus"] == "user") {
		$showde = 'none';
		$logform = 'none';
		$review = "";
	}
}
?>

<?php
mysql_query("SET NAMES UTF8");
$sql1 = "select * from service_other ";
$mydata1 = mysql_query($sql1);
$num = mysql_num_rows($mydata1);

mysql_query("SET NAMES UTF8");
$sqlcompare = "SELECT r_rest, r_type,count(r_status) as r_st,r_price  FROM room where r_status = 1 GROUP BY r_type";
$mydatacom = mysql_query($sqlcompare);
?>

<script type="text/javascript">
	function changedate() {
		document.getElementById('chosech').style.display = "";
		document.getElementById('showdatenum').style.display = "none";
		document.getElementById('facilities').style.display = "none";
		document.getElementById('inpu').style.display = "none";
		document.getElementById('room_selected1').style.display = "none";

	}

</script>

<div id="warp">
<?php
include ("sidebar.php");
?>
<div class="col_right">
<h1 style="margin: 0 0 10px 0;font-size: 23px;"><?=$rname; ?></h1>
<div class="image"><img src="images/room/<?=$picture; ?>" alt="#" width="200" height="150">
</div>
<div class="detail">
<p class="hdetail">
<?=$detail; ?>
</p>
</div>
<form method="post" action="<?=$_SERVER["PHP_SELF"]; ?>?name=<?=$rname; ?>&id=<?=$rid; ?>&stat=check" name="frmm">
<div class="box2" id="chosech" style="display: <?=$chosech; ?>;">
<div style="margin-left: 60px">
วันที่ Check In :
<input name="date" id="date" size="20" value="<?=$datenow; ?>">
<a href="javascript:displayDatePicker('date')"><img border="0" src="images/calendar_2.png" width="16" height="16"></a>
วันที่ Check Out : <span id="datecheckout"></span>
<input name="date2" id="date2" size="20" value="<?=$datecho; ?>">
<a href="javascript:displayDatePicker('date2')"><img border="0" src="images/calendar_2.png" width="16" height="16"></a>
<br><div style="margin-left: 218px;margin-top: 0px;">
<input type="submit" class="chk-rate-btn searchhotel" value="คำนวณราคาห้องพัก" />
</div>
</div>
</div>
</form>

<form method="post" action="checkinform_true.php?roomid=<?=$rid; ?>" name="formche" onsubmit="return submitform();">
<input type="hidden" name="roomname" value="<?=$rname; ?>" />
<input type="hidden" name="roomtype" value="<?=$rtype; ?>" />
<div class="box2" id="showdatenum" style="display: <?=$showdatenum; ?>;">
<div style="margin-left: 60px">
วันที่ Check In :
<input name="date3" id="date3" size="20" value="<?=$datechin; ?>" readonly="true">
วันที่ Check Out : <span id="datecheckout"></span>
<input name="date4" id="date4" size="20" value="<?=$datechou; ?>" readonly="true">
<br><br>
คุณเข้าพักจำนวน <font color="red"><?=$dayyy; ?></font> วัน <font color="red"><input type="hidden" name="allday" value="<?=$allday; ?>" /><?=$allday; ?></font> คืน ราคาที่พัก  <font color="red"><?=$money; ?></font> บาท
</div><a href="javascript:changedate();"><span class="change_date" id="change_date1">เปลี่ยนรายละเอียดการจอง</span></a>
</div>

<table class="roomtype" id="room_selected1" style="display: <?=$showdatenum; ?>;border-spacing: 0px;">
<tr>
<td colspan="2">
<p align="center">ประเภทห้องพัก</p>
</td>
<td colspan="1">
<p align="center">เหลือ (ห้อง)</p>
</td>
<td align="center" width="75">พักได้ (คน)</td>

<td align="center" width="183">รวมราคา (บาท)</td>
</tr>
<?php
$icom = 0;
while($rowcom=mysql_fetch_array($mydatacom))
{
$rtypecom = $rowcom["r_type"];
$rrestcom = $rowcom["r_rest"];
$rpricecom = $rowcom["r_price"];
$rst = $rowcom["r_st"];
$moneycom = $rpricecom * $allday;
?>
<tr class="tt">

<td width="390" rowspan="1" colspan="2" valign="middle">
<p class="rname">
<b><?=$rtypecom; ?></b>  >> <a href="searchResult.php?type=<?=$rtypecom; ?>">คลิ๊ก !</a>
</p> 
</td>
<td width="100" rowspan="1" colspan="1" valign="middle" align="center">
<p class="rrest">
<?=$rst; ?>
</p>
</td>
<td align="center" width="74"><span class="rest"><?=$rrestcom; ?> </span></td>
<td class="avgprice" align="center" rowspan="1" width="183">
<font style="font-size: 18px; color: #E30000;"><?=$moneycom; ?></font>
</td>
</tr>
<?
}
?>
</table>

<div class="facilities" id="facilities" style="display: <?=$showdatenum; ?>;">
<h2 id="บริการ">บริการเสริมอื่นๆ:</h2>
<div class="facdetail">
<center>
<table width="600" border="0" >
<tr>
<td align="center">เลือก</td>
<td align="center">รายการ</td>
<td align="center">ราคา / Package</td>
</tr>
<?php
$serr = 0;
while($row1=mysql_fetch_array($mydata1))
{
$sid = $row1["s_id"];
$sname = $row1["s_name"];
$sprice = $row1["s_price"];
?>
<tr><input type="hidden" name="serid[]" value="<?=$sid; ?>" />
<td align="center"><input type="checkbox" name="ser[]"  id="ser" value="<?=$serr; ?>">
</td>
<td align="center"><input type="hidden" name="nameservice[]" value="<?=$sname; ?>" />
<?=$sname; ?></td>
<input type="hidden" name="price[]" value="<?=$sprice; ?>" />
<td align="center"><?=$sprice; ?></td>
</tr>
<?
$serr++;
}
?>
<input type="hidden" value="<?=$serr; ?>" id="number" />
</table>
</center>
</div>
</div>
<center>
<div id="inpu" style="display: <?=$showde; ?>;">
<?
$_SESSION["url"] = $_SERVER["PHP_SELF"] . '?name=' . $rname . '&id=' . $rid . '&stat=';
?>
<input type="submit" class="chk-rate-btn searchhotel" value="จองห้องพัก" />
</div>
</center>
</form>
<br>
<!--แสดงรีวิว-->
<?
mysql_query("SET NAMES UTF8");
$sqlshowre = "select * from review where re_rid = $rid";
$objQuery = mysql_query($sqlshowre);
$numr = mysql_num_rows($objQuery) or die($sqlshowre);
?>
<div id="reviews-container">
	<div style="border-right:1px solid #C2BFBF;width:200px;height:23px;float:left;padding:0 0 0 15px;line-height: 20px;">
		All Reviews For Room (<b><?=$numr; ?></b>)
	</div>
	<div style="border-right:1px solid #C2BFBF;width:280px;height:23px;float:left;padding:0 0 0 15px;">	
		Overall Reviews
	</div>	
	<div style="clear: both;"></div>
</div>
<div style="clear: both;"></div>
<!--แสดงรีวิว-->
<!--รีวิว-->

<?
if ($_POST["txtreviews"]!=""){
	$content = $_POST["txtreviews"];
	$cid = $_COOKIE["cid"];
	$rating = $_POST["rating"];
	$sqlreview = "insert into review (re_rid,re_content,re_cid,re_rating,re_approve)
	values($rid,'$content',$cid,$rating,1)" ;
	mysql_query("SET NAMES UTF8");
	$objQuery = mysql_query($sqlreview);
	////////////////////////
	
}
?>
<br>
<div id="comment-container" style="display: <?=$review; ?>;">
	<h2>แนะนำ และ รีวิว</h2>
	<form method="post" action="" class="comment">
		<br>
		<div style="float: left;">
			<b>ให้คะแนน </b> <br><input type="radio" name="rating" value="5" checked="checked" /> 5 คะแนน
			<br><input type="radio" name="rating" value="4" /> 4 คะแนน
			<br><input type="radio" name="rating" value="3" /> 3 คะแนน
			<br><input type="radio" name="rating" value="2" /> 2 คะแนน
			<br><input type="radio" name="rating" value="1" /> 1 คะแนน	
		</div>
		<div style="float: left;margin-left: 20px;">
			<b>แสดงความคิดเห็น </b> <br>
			<textarea cols="50" rows="5" name="txtreviews" placeholder="แสดงความคิดเห็น"></textarea>
		</div>
		<div style="float: left;margin-left: 20px;margin-top: 47px;">
		<input type="submit" value="แสดงความคิดเห็น" />	
		</div>
		<div style="clear: both;"></div>
	</form>
</div>	

<!--รีวิว-->

<div style="clear: both;"></div>
<br>
<div id="logform" style="display: <?=$logform; ?>;">
<div style="text-align:center;color:#888;">---- กรุณาใส่  'ชื่อบัญชีและรหัสผ่าน'  ก่อนทำการ <b>จอง</b> และ  <b>Review</b> ----</div>
<div style="text-align:center;color:#888;">
<form method="post" action="logincheck.php">
Email <input type="text" name="login_email"><br>
Password <input type="password" name="login_pass"><br>
<input type="hidden" name="urlpage" value="<?=$_SERVER["PHP_SELF"]; ?>?name=<?=$rname; ?>&id=<?=$rid; ?>">
<input type="submit" name="submit" value="เข้าสู่ระบบ ">
</form>
</div>
</div>
</div>
<?php
ob_end_flush();
include ("footer.php");
?>