trying to echo a variable dynamically

matthewst · July 7, 2007

I have a simple game script here http://matthews.gotdns.org/game/test_game.php

test_game.php

<?php
mysql_connect("localhost", "user", "pass") or die(mysql_error());
mysql_select_db("test_game") or die(mysql_error());
//error_reporting(E_ALL);
error_reporting(0);
?>

<?php
$query = "SELECT player_name, hit_points FROM users"; 
$result=mysql_query($query);
while ($row = mysql_fetch_assoc($result))
{
$player_name = $row['player_name'];
$hit_points = $row['hit_points'];
if($hit_points <= "0")
{
echo "$player_name is dead&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp";
}
else
{
echo "Player: $player_name&nbsp";
echo "Hit points: $hit_points&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp";
}
}
?>
<title>test game</title>
</head>
<body>
<br>
<a href="atk.php?p=2">hit player two</a>&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp
<a href="atk.php?p=1">hit player one</a>
</body>
</html>

atk.php

<?php
mysql_connect("localhost", "root", "root") or die(mysql_error());
mysql_select_db("test_game") or die(mysql_error());
//error_reporting(E_ALL);
error_reporting(0);
?>
<?php
if($_GET['p'] == 2){ 
$sql = "UPDATE users SET hit_points=hit_points-1 WHERE player_name = 'player_2'"; 
mysql_query($sql)or die(mysql_error());
}
if($_GET['p'] == 1){ 
$sql = "UPDATE users SET hit_points=hit_points-1 WHERE player_name = 'player_1'"; 
mysql_query($sql)or die(mysql_error());
}

echo "<script type='text/javascript'>
<!--
window.location = 'test_game.php'
//-->
</script>";
?>

what I'm trying to accomplish is:

I have the page loaded on my computer

you have the page loaded on you computer

I click "hit_player_2" and the page on your computer is updated (you lose a hit point) automatically without a refresh

I don't wan't anyone to write the script for me (I can't learn that way). I just need someone to point me in a direction or give me a few key words to serach for. I've already read the tutorials but couldn't find anything pertaining to this problem.

matthewst · July 7, 2007

I originally used a form but it didn't work as expected. It would take a point away from the wrong player the first time you clicked a button.

<?php
mysql_connect("localhost", "user", "pass") or die(mysql_error());
mysql_select_db("test_game") or die(mysql_error());
//error_reporting(E_ALL);
error_reporting(0);
?>
<?php
$query = "SELECT player_name, hit_points FROM users"; 
$result=mysql_query($query);
while ($row = mysql_fetch_assoc($result))
{
$player_name = $row['player_name'];
$hit_points = $row['hit_points'];
if($hit_points <= "0")
{
echo "$player_name is dead&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp";
}
else
{
echo "Player: $player_name&nbsp";
echo "Hit points: $hit_points&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp";
}
}
?>
<title>test game</title>
</head>
<body>
<br><form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="FormName"><input name="hit_player_2" type="submit" value="hit_player_2">
&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp<input name="hit_player_1" type="submit" value="hit_player_1"></form>
<?php
if(isset($_POST['hit_player_1'])){ 
     $sql = "UPDATE users SET hit_points=hit_points-1 WHERE player_name = 'player_1'"; 
     mysql_query($sql)or die(mysql_error());
}
if(isset($_POST['hit_player_2'])){ 
     $sql = "UPDATE users SET hit_points=hit_points-1 WHERE player_name = 'player_2'"; 
     mysql_query($sql)or die(mysql_error());
}
?>
</body>
</html>

bibby · July 7, 2007

matthewst, your php and mysql look just fine as your tests show. To have this dynamic processing both on the server side, and the client side without a refresh, you ought to lookup and realy get to know javascript.

words to search for are javascript, events, onclick, ajax, xmlhttp;

There is a thread with a lot of good code I participated in today that's worth a peek. http://www.phpfreaks.com/forums/index.php/topic,148418.0.html

Javascript and the DOM have broken down the elements on a page to the point where one can query the server for a single value (like player1's HP) and replacing the content of an html element -> in this case perhaps, the html element that contains within it the current player1 HP (span, p, div).

matthewst · July 17, 2007

ok, heres what i have now

needless to say, it doesn't work

game.php

<?php
mysql_connect("localhost", "user", "pass") or die(mysql_error());
mysql_select_db("test_game") or die(mysql_error());
//error_reporting(E_ALL);
error_reporting(0);
?>
<?php
$query = "SELECT player_name, hit_points FROM users"; 
$result=mysql_query($query);
while ($row = mysql_fetch_assoc($result))
{
$player_name = $row['player_name'];
$hit_points = $row['hit_points'];
if($hit_points <= "0")
{
echo "$player_name is dead&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp";
}
else
{
echo "Player: $player_name&nbsp";
echo "Hit points: $hit_points&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp";
}
}
?>
<head>
<title>test game</title>
<script language="javascript">
    function createRequestObject() {
    
        var req;
    
        if(window.XMLHttpRequest){
            // Firefox, Safari, Opera...
            req = new XMLHttpRequest();
        } else if(window.ActiveXObject) {
            // Internet Explorer 5+
            req = new ActiveXObject("Microsoft.XMLHTTP");
        } else {
            // There is an error creating the object,
            // just as an old browser is being used.
            alert('There was a problem creating the XMLHttpRequest object');
        }
    
        return req;
    
    }
    
    // Make the XMLHttpRequest object
    var http = createRequestObject();


function sendRequest(act) {
        
        // Open PHP script for requests
        http.open('get', 'atk.php?act='+act);
        http.onreadystatechange = handleResponse;
        http.send(null);
    
    }
    
    function handleResponse() {
    
        if(http.readyState == 4 && http.status == 200){
    
            // Text returned FROM PHP script
            var response = http.responseText;
    
            if(response) {
                // UPDATE ajaxTest content
                document.getElementById("atk").innerHTML = response;
                setTimeout(atk,5000);
            }
    
        }
    }

</script>
</head>
<body>
<br>
<a href="atk.php?p=2">hit player two</a>&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp
<a href="atk.php?p=1">hit player one</a>
<?PHP
function countPosts() {
        sendRequest('atk');
    }
?>

</body>
</html>

atk.php

<?php
mysql_connect("localhost", "root", "root") or die(mysql_error());
mysql_select_db("test_game") or die(mysql_error());
//error_reporting(E_ALL);
error_reporting(0);
?>
<?php
if($_GET['p'] == 2){ 
$sql = "UPDATE users SET hit_points=hit_points-1 WHERE player_name = 'player_2'"; 
mysql_query($sql)or die(mysql_error());
}
if($_GET['p'] == 1){ 
$sql = "UPDATE users SET hit_points=hit_points-1 WHERE player_name = 'player_1'"; 
mysql_query($sql)or die(mysql_error());
}

echo "<script type='text/javascript'>
<!--
window.location = 'test_game.php'
//-->
</script>";
?>

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trying to echo a variable dynamically

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