Updating 'credits' using PHP and JavaScript

Question

So I'm working on a website that involves credits. I've been researching the Internet for about 30 minutes now, trying to figure a solution for updating credits. By updating credits I mean this.

The webpage loads credits from the MySQL database, the player then uses a portion of some credits (Keep in mind I have subtracted them once used), but they don't update when subtracted.

So I used a JavaScript method that sets the credits to a LI in HTML. I use PHP inside of the JavaScript code. HOWEVER, it retrieves an amount of credits, but it's not the update amount of credits. It's the previous or it stays frozen on the previous amount of credits.

So here is the code you'll need to know the most:

This supposedly 'updates' the LI using JavaScript and PHP:

function finalL(){
document.getElementById("updatecredits").innerHTML = "credits: " + 
<?php

$db = mysqli_connect('localhost', 'root', 'iGenX772', 'userdata');

$query = mysqli_fetch_array(mysqli_query($db, "SELECT credits FROM users          WHERE username='" . mysqli_real_escape_string($db, $_SESSION['user']  ['username']) . "'"));
echo $query['credits'];

mysqli_close($db);
?>;
}

First called when the PHP page loads:

<li><a id="updatecredits">Credits:
<?php

$db = mysqli_connect('localhost', 'root', 'iGenX772', 'userdata');

$query = mysqli_fetch_array(mysqli_query($db, "SELECT credits FROM users WHERE username='" . mysqli_real_escape_string($db, $_SESSION['user']['username']) .   "'"));
echo $query['credits'];

mysqli_close($db);

?></a></li>

I activate the function through another part which is probably unnecessary for any use for this issue. BUT I am subtracting the credits BEFORE this function is called.

I use the same method in the function as I do in the List. If anyone has a solution to this issue, I would love it!

~mrgreen33gamer | Joshua

EXTRA:

<div id="logreg">
<ul>
<li><a>Welcome, <?php echo htmlentities($_SESSION['user']['username'],    ENT_QUOTES, 'UTF-8'); ?></a></li>
<li><a><span id="updatecredits">Credits:
<?php

$db = mysqli_connect('localhost', 'root', 'iGenX772', 'userdata');

$query = mysqli_fetch_array(mysqli_query($db, "SELECT credits FROM users WHERE username='" . mysqli_real_escape_string($db, $_SESSION['user']['username']) . "'"));
echo $query['credits'];

mysqli_close($db);

?></span></a></li>
<li><a href="logout.php">Logout</a></li>
</ul>
</div>

Gerard · Accepted Answer · 2016-05-04T02:42:22.057

0

You should call the PHP using Ajax and put the PHP code into a separate file. In this case I assume the PHP code is in loadCredits.php

Javascript

<script type="text/javascript">
function finalL(){          
  xhttp= new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (xhttp.readyState == 4 && xhttp.status == 200) {
      document.getElementById("updatecredits").innerHTML = "Credits: " + xhttp.responseText;
    }
  };
  xhttp.open("GET", "loadCredits.php?t=" + Math.random(), true);
  xhttp.send();
}
</script>

PHP

<?php
echo (5);
?>

HTML

<ul>
<li><a>Welcome, </a></li>
<li><a><span id="updatecredits" onClick="finalL()">Credits:
</span></a></li>
<li><a href="logout.php">Logout</a></li>
</ul>

edited May 04 '16 at 02:42

answered May 04 '16 at 01:37

Gerard

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Okay so I replaced the function with your current once. I get a giant error in console saying that the '$' before '.ajar({' is not defined.... – Joshua Feliciano May 04 '16 at 01:52
So you don't use jQuery. I have updated the code. – Gerard May 04 '16 at 02:15
Actually, it's not showing the credits at all.... – Joshua Feliciano May 04 '16 at 02:21
Maybe you can post the HTML you use? It should only update the element updatecredits. – Gerard May 04 '16 at 02:22
Alrighty, sir. I have updated the code at the bottom of the post. Under: EXTRA – Joshua Feliciano May 04 '16 at 02:25
I have tested the updated code and it works fine. You will have to use your own PHP code to generate the number of credits – Gerard May 04 '16 at 02:43
Yo thanks a million man!!! Not only have you helped me solve my issue, but you've helped the community with answers, and now I've learned a lot more about PHP and HTML! Great work Gerard, I wish you the best of luck from here on forth! – Joshua Feliciano May 04 '16 at 02:54

Updating 'credits' using PHP and JavaScript

1 Answers1