如何显示所选下拉菜单中的类别之一

Question

I need help with the code below - I'm trying to display one of the categories like 'genre' or 'platform' when the user selects one of them from the first drop-down menu. I don't know how I would do this

<?php # browser_catalog.php 
include ('includes/session.php');

$page_title = 'Browser Games Catalog';
include ('includes/header.php');

require_once ('mysqli_connect.php'); // Connect to the db.

// Check if the form has been submitted:
if (isset($_POST['submitted'])){

    $errors = array(); // Initialize an error array.

    // Check for a game name:
    if (empty($_POST['cat1'])) {
            $errors[] = 'You forgot to enter game name.';
    } else {
            $where = mysqli_real_escape_string($dbc, trim($_POST['cat1']));
    }

    if (empty($_POST['cat2'])) {
            $errors[] = 'You forgot to enter game name.';
    } else {
            $what = mysqli_real_escape_string($dbc, trim($_POST['cat2']));
    }

    if($where == "Genre"){

        $q = "SELECT game_name AS game, 
        platform AS pf, 
        genre AS ge, 
        game_description AS gd,
        game_price AS gp, 
        game_image AS gi,
        game_headlines AS gh
        FROM game
        WHERE  genre = '$what'";
    }
    else{

        $q = "SELECT game_name AS game, 
        platform AS pf, 
        genre AS ge, 
        game_description AS gd,
        game_price AS gp, 
        game_image AS gi,
        game_headlines AS gh
        FROM game
        WHERE platform = '$what'";
    }

    $r = \mysqli_query($dbc, $q); // Run the query.

    // Count the number of returned rows:
    $num = mysqli_num_rows($r);

    if ($num > 0) { // If it ran OK, display the records.

        echo "<p>There are currently $num number of games for '$search'.</p>\n";

        // Table header.
        echo '<table align="center" cellspacing="3" cellpadding="3" width="75%">
            <tr>
            <br>    &#09;<td align="left" padding-left:5px><b>Game Name</b></td>
            <br>    &#09;<td align="left" padding-left:5px><b>Platform</b></td>
            <br>&#09;<td align="left"><b>Genre</b></td>
            <br>    &#09;<td align="left"><b>Game Description</b></td>
            <br>    &#09;<td align="left"><b>Game Price</b></td>
            <br>    &#09;<td align="left"><b>Game Image</b></td>
            <br>    &#09;<td align="left"><b>Game Headlines</b></td>
            </tr>';

        // Fetch and print all the records:
        //<td align="left">' . "<img src = images/web/" . $row['gi']  "/>".  '</td>
        while ($row = mysqli_fetch_array($r, MYSQLI_ASSOC)) {

            echo '<tr>

                <br>    &#09;<td align="left">' . $row['game'] . '</td>
                <br>    &#09;<td align="left">' . $row['pf'] . '</td>
                <br>    &#09;<td align="left">' . $row['ge'] . '</td>
                <br>    &#09;<td align="left">' . $row['gd'] . '</td>
                <br>    &#09;<td align="left">' . $row['gp'] . '</td>
                <br> <td align="left">' . $row['gh'] . '</td>

                </tr>'; 
        }       

        echo '</table>'; // Close the table.
        mysqli_free_result ($r); // Free up the resources.  

    } else { // If no records were returned.

        echo '<p class="error">There are currently no registered users.</p>';

    }

    mysqli_close($dbc); // Close the database connection.
}
?>

<div class="page-header">

    <h1 style="font-size:40px"><center></center></h1>
</div>
<form class="form-signin" role="form" action="browser_catalog.php" method="post">


    <?php
    <p>Choose a Category:   
        <select class="form-control" id="element_6" name="category"  value="<?php if (isset($_POST['cat1'])) echo $_POST['cat1']; ?>" /> 
                <option>Platform</option>
                <option>Genre</option>
        </select>
    </p>

    if($cat1 == "Platform"){        
        <p>Platform:    
            <select class="form-control" id="element_6" name="platform"  value="<?php if (isset($_POST['cat2'])) echo $_POST['cat2']; ?>" /> 
                    <option >PC</option>
                    <option >PS4</option>
                    <option >Xbox One</option>
                    <option >Wii U</option>
                    <option >PS3</option>
                    <option >Xbox 360</option>
                    <option >Wii</option>
                    <option >Mac</option>
                    <option >Linux</option>
                    <option >Nintendo 3DS</option>
                    <option >DS</option>
                    <option >PS2</option>
                    <option >iPhone</option>
                    <option >Android</option>
            </select>
        </p>
    }
    else{
        <p>Genre:   
            <select class="form-control" id="element_6" name="genre"  value="<?php if (isset($_POST['cat2'])) echo $_POST['cat2']; ?>"> 
                <option>Action</option>
                <option>Adventure</option>
                <option>Driving</option>
                <option>RPG</option>
                <option>Strategy</option>
                <option>Sport</option>
                <option>Puzzle</option>
            </select>
        </p>
    }
    ?>
    <button style="display:inline; padding:10px; margin-bottom:5px" type="submit" name="submit" class="btn btn-sm btn-primary" />Search Game</button>
    <input type="hidden" name="submitted" value="TRUE" /></p></center>

</form>

<?php
include ('includes/footer.html');
?>

Answer 1

First you have a typpo here

<p>Choose a Category:   
        <select class="form-control" id="element_6" name="category"  value="<?php if (isset($_POST['cat1'])) echo $_POST['cat1']; ?>" /> 
                <option value=>Platform</option>
                <option >Genre</option>
        </select>
    </p>

here:

<option value=>Platform</option>

Then you did not open php tags when writting php. example here

if($cat1 == "Platform"){      

Before this, and after end of html you should open php tags like this

<?php
if($cat1 == "Platform"){   

Also on lots of places you mixing html and php

Also here mixing html and php. No opening and closing php tag

    </p>
    }
    else{
        <p>Genre:

Also I will recommend you to use <input type='submit'> instead of <button type='submit'> for submititng form.

Anyway it will be good to edit your question and fix syntax on your code and then we can focus on your problem and you will need to be more precise what is really a problem with code. Thanks Edit: Here is one example how to do it

// not here remove this line ->    <?php
<p>Choose a Category:   
    <select class="form-control" id="element_6" name="category"  value="<?php if (isset($_POST['cat1'])) echo $_POST['cat1']; ?>" /> 
            <option>Platform</option>
            <option>Genre</option>
    </select>
</p>
// But instead here put  <?php
if($cat1 == "Platform"){ 
// And here close it ->   ?>  

Rest you must do for yourself since I can not write full code for you, and is also good for you to learn on your own mistakes, and I can be here to provide help if I can. Read w3 school website, there you can find basics of how to properly write php and html