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Dynamic Dropdown Lists


pbrandy22

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Hi everyone,

 

I've read through the FAQs for Dynamic Dropdown Menus on this site, as well as others, and I can't figure out why my code won't work. I have two dropdown boxes that need to be populated with data from a mysql table; one menu for route types, and one for route numbers. When I choose the route from the 'Route' menu, the 'Number' menu automatically populates with all of the possible numbers, rather than only those that correspond with the route type. I can tell that the problem has something to do with the value of 'Route' not being recognized, but I don't know why. I'm a beginner when it comes to PHP, so any suggestions or help would be much appreciated!  Thanks!

 

The code is as follows:

 


<html> 
<body> 
<basefont face='calibri' color='#7E2217'> 
<?php 
// set variables 
$mileTable = $_GET['mileTable']; 
$routeType = isset($_POST['Roadtype'])? $_POST['Roadtype']: 0; 
include 'opendbMile.php'; 
include 'error.php'; 
    // Connect to the MySQL DBMS 
   if (!($connection = @ mysql_connect($hostName, 
                                                                           $username, 
                                                                           $password))) 
          die("Could not connect"); 
   if (!mysql_select_db($databaseName, $connection)) 
         showerror(  ); 

    // Start a query... 
    $query = "SELECT ID, 
                                         Roadtype 
                          FROM Alabama 
                          GROUP BY Roadtype"; 
    // execute the SQL statement 
    $result = mysql_query($query, $connection) or die(mysql_error()); 
echo '<form name="mileform" method="post" action="MileQuery.php">'; 
echo '<p>Route: 
<select name="routeType" id="routeType" onchange="this.form.submit();"> 
<option value="0"'.($routeType == 0? ' SELECTED': '').'>Route</option>'; 
while($row = mysql_fetch_array($result)){ 
    echo ' 
            <option value="'.$row[0].'"'.(($routeType == $row[0])? ' SELECTED': '').'>'.$row[1].'</option>'; 
} 
    echo ' 
    </select> 
</p>'; 
// create the SQL statement 
$query2 = "SELECT ID, 
          Roadnumber 
                   FROM Alabama 
                   GROUP BY Roadnumber"; 
         if($mnucategory != 0){    // Filter road numbers 
    $query2 .= " WHERE Roadtype='".$routeType."'"; 
    } 
// execute the SQL statement 
$result2 = mysql_query($query2, $connection) or die(mysql_error()); 
echo '<p>Number: 
    <select name="routeNumber" id="routeNumber" onchange="this.form.submit();"> 
            <option value="0"'.($routeNumber == 0? ' SELECTED': '').'>Number</option>'; 
while($row2 = mysql_fetch_array($result2)){ 
    echo ' 
            <option value="', $row2[0].'"'.(($routeNumber == $row2[0])? ' SELECTED': '').'>'. $row2[1], '</option>'; 
} 
    echo ' 
    </select> 
</p>'; 
// Close the DBMS connection 
   mysql_close($connection); 
?> 
</form> 
</body> 
</html>

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