php如何确保重新加载页面并将echo更新为新值

Question

The users of my website can subscribe some of their animals for a competition. My code works perfectly but there is a big issue. When a user presses subscribe the page reloads but because the isset is after the echo of the button itself the page needs to be refreshed before the buttontext changes into "subscribed". Change the order gives issues as you probably can see. Who can help me out? I'm out of options myself. (I translated the variables etc.)

<form action="" method="post" name="frmSubscribe">
<?php
$Counter = 0;
$sql = "Select * from Animals where username='".$_SESSION['User']."' ";
$result = mysql_query($sql);
while($row=mysql_fetch_array($result)){

    echo $row['Animalname'];
    $Duiven[] = $row['AnimalID'];
    $Username[] = $row['username'];

    ?>
    <input type='submit' <?php echo "name= ".$Buttons[$Counter].""; ?> value='<?php 
    $sqlSubscribed = "SELECT * FROM Competitionresults WHERE AnimalID='".$Animals[$Counter]."'";
    $resultSubscribed = mysql_query($sqlSubscribed);
    if(mysql_num_rows($resultSubscribed) == 0){ echo "Subscribe";}
    else {echo "deregister";}
    ?>'><br/><?php
    $Teller++;
    }

if (isset($_POST['btnSubscribe1'])){

$sqlCheck = "SELECT * FROM Competitionresults WHERE AnimalID='".$Animals[0]."'";
    $resultCheck = mysql_query($sqlCheck);
    if (mysql_num_rows($resultCheck) == 0){

    $sql1 = "INSERT INTO Competitionresuls (AnimalID, username) VALUES ('".$Animals[0]."','".$Username[0]."')";
    $result1 = mysql_query($sql1);
    $row=mysql_fetch_array($result1);
    ?><?php
    }
    }

... and so on for the next animals.

Answer 1

You have to use output buffering I think. Put ob_start() at the beginning of your page, now output any placeholder instead of real input code:

[SUMBIT]

instead of:

<input type='submit' ....

At the end of page you get your buffered content:

$content = ob_get_clean()

And replace submit button with correct code:

$content = str_replace('[SUBMIT]', 'Your actual submit button code here...', $content);

And now output content:

echo $content;

Answer 2

quick fix can be javascript

echo '<span id="someid" >Subscribe</span>';

and when changing

echo "<script>document.getElementById('someid').innerHTML = 'Subscribed';</script>";

in future I STRONGLY suggest you to use PHP MVC Framework

Answer 3

You can use your post code above the page then loaded your page.... Please use like below code:

 <?php
    if (isset($_POST['btnSubscribe1'])){

    $sqlCheck = "SELECT * FROM Competitionresults WHERE AnimalID='".$Animals[0]."'";
        $resultCheck = mysql_query($sqlCheck);
        if (mysql_num_rows($resultCheck) == 0){

            $sql1 = "INSERT INTO Competitionresuls (AnimalID, username) VALUES ('".$Animals[0]."','".$Username[0]."')";
           mysql_query($sql1);
           header('Location: samefilename.php');
           die;
         }

        }
    ?>
    <form action="" method="post" name="frmSubscribe">
    <?php
    $Counter = 0;
    $sql = "Select * from Animals where username='".$_SESSION['User']."' ";
    $result = mysql_query($sql);
    while($row=mysql_fetch_array($result)){

        echo $row['Animalname'];
        $Duiven[] = $row['AnimalID'];
        $Username[] = $row['username'];

        ?>
        <input type='submit' <?php echo "name= ".$Buttons[$Counter].""; ?> value='<?php 
        $sqlSubscribed = "SELECT * FROM Competitionresults WHERE AnimalID='".$Animals[$Counter]."'";
        $resultSubscribed = mysql_query($sqlSubscribed);
        if(mysql_num_rows($resultSubscribed) == 0){ echo "Subscribe";}
        else {echo "deregister";}
        ?>'><br/><?php
        $Teller++;
        }


        }

Answer 4

most easy solution move the isset up to the top. just so you know actions should always be the first things you handle after that you are gonna work on the view

<form action="" method="post" name="frmSubscribe">
<?php

if (isset($_POST['btnSubscribe1'])){

$sqlCheck = "SELECT * FROM Competitionresults WHERE AnimalID='".key($_GET)."'";
$resultCheck = mysql_query($sqlCheck);
if (mysql_num_rows($resultCheck) == 0){

$sql1 = "INSERT INTO Competitionresuls (AnimalID, username) VALUES ('".key($_GET)."','".$_SESSION['User']."')";
$result1 = mysql_query($sql1);
$row=mysql_fetch_array($result1);

}
}

$Counter = 0;
$sql = "Select * from Animals where username='".$_SESSION['User']."' ";
$result = mysql_query($sql);
while($row=mysql_fetch_array($result)){

echo $row['Animalname'];
$Duiven[] = $row['AnimalID'];
$Username[] = $row['username'];

?>
<input type='submit' <?php echo "name= ".$Buttons[$Counter].""; ?> value='<?php 
$sqlSubscribed = "SELECT * FROM Competitionresults WHERE AnimalID='".$Animals[$Counter]."'";
$resultSubscribed = mysql_query($sqlSubscribed);
if(mysql_num_rows($resultSubscribed) == 0){ echo "Subscribe";}
else {echo "deregister";}
?>'><br/><?php
$Teller++;
}