อธิบายการ php login โดยใช้ cookies หน่อยนะค่ะ ไม่เคยใช้ค่ะ

// Check User Password
function checkpass($newPW,$existPW){
	if($newPW == $existPW){
		return true;	
	}else{
		return false;	
	}		
}

// Check User Email
function checkemail($email,$exist_mail){			
	if($email == $exist_mail){	
		return true;	
	}else{
		return false;	
	}	
}

//////////////////////////////////////////////////////////////////////////////

include("config.php");

$email		= $_POST['email'];
$getPass 	= md5($_POST['pass']);
$remember	= $_POST['chkbox'];

////////   Message Feedback   ///////////

$err1 = 'Email ไม่มี email นี้ในระบบ';
$err2 = 'Password ไม่ถูกต้อง';

	$q = mysql_query("select * from tb_member  where e_mail like '$email'");
	$r = mysql_num_rows($q);
	$r = mysql_fetch_array($q);
	
	if($r != 0){
		$q_mail = $r['e_mail'];
		$q_password = $r['password'];
	}else{
		$q_mail = '-';
		$q_password = '-';
	}
	
	

// Call Back Result
if(checkemail($email,$q_mail) && checkpass($getPass,$q_password)){
	
	if($remember == 'true'){
		setcookie("userID_log",$r['userId'],time()+3600*24*356);
		setcookie("userName_log",$r['username'],time()+3600*24*356);
		setcookie("userLevel",$r['level'],time()+3600*24*356);
		
	}
	echo '
	<div class="loginform">
       <div class="formdetails">
	        <div class="user-img">
            	<img src="regular-user.jpg" width="60" height="50" >
            </div>
            <div class="user-detail-wrap">
            	<div style="font-size:12px; padding:0 0 3px 0; margin:0 0 3px 0; border-bottom:1px solid #333;">สวัสดีคุณ <b>'.$r['username'].'</b> </div>
                <div><a class="user-edit" href="#">เเก้ข้อมูลส่วนตัว</a></div>
            </div>
            <div>
            	<input id="logout" name="logout" type="button" value="Logout" onclick="Logout()" />
            </div>
		</div>
	</div>		
	';
}else{
	echo '
	<div class="loginform">
       <div class="formdetails">
        <form name="form" action="" method="post">
            <div id="error-warp">
		';
	if(checkemail($email,$q_mail)){
		echo'
		   		<div class="err" id="err-mail" style="visibility:hidden"></div>
		';
	}else{
		echo'
				<div class="err" id="err-mail" style="visibility:visible">'.$err1.'</div>
		';		
	}
	
		if(!checkemail($email,$q_mail)){			
	echo'
			<div class="err" id="err-pass" style="visibility:hidden"></div>
		';
	}else{
		echo'
			<div class="err" id="err-pass" style="visibility:visible">'.$err2.'</div>
		';	
	}
	
	
    echo'            
            </div>
        	<label for="log">Email : </label> 
		';  
	if(checkemail($email,$q_mail)){		     
         	echo '<input id="mail" name="email" type="text" value="'.$email.'"  style="margin:0 11px 0 0;" />';
	}else{
		    echo '<input id="mail" name="email" type="text"  style="margin:0 11px 0 0;" />';
	}
	echo '
        	<label for="pwd">Password : </label>
        	<input id="pass" name="passwor" type="password"  />
        	<input id="btn" name="Login" type="button" value="Login" onclick="postEmail()" style="margin:0 11px 0 10px;"  />
        	<label for="rememberme"><input name="rememberme" id="rememberme" type="checkbox" checked="checked" value="forever" /> จำฉันไว้ในระบบ</label><input type="hidden" name="redirect_to" value="" />
        	</form>
			
		</div>
		
		<div class="loginregister">
        <a href="#">สมัครสมาชิก</a> |
        <a href="#">ขอรหัสผ่านใหม่</a>
        </div>
		
	</div>		
	';
}
?>

<?PHP
echo $r['userId']; //ดูว่ามีค่ารึป่าวครับ
?>

$userId = $r['userId'];
mysql_query("INSERT INTO imades(userId) VALUES('$userId')");