Im making a function that are getting information from my SQL server. What im trying to make it do is the following:

1. Fill a dropdown list. WORKING
2. Select from dropdown list. NO CLUE.

3. SQL query with the selected dropdown value. KIND OF KNOW
   "Austmann" will be changed with the selected value

   function runMyFunction() {
   
   $result = mysql_query("SELECT * FROM olsortriment WHERE bryggeri ='austmann'") 
   
   or die(mysql_error());  
   
   echo "<table border='1'>";
   echo "<tr> <th>Name</th> <th>Age</th> </tr>";
   
   while($row = mysql_fetch_array( $result )) {
      echo "<tr><td>"; 
      echo $row['navn'];
      echo "</td><td>"; 
      echo $row['bryggeri'];
      echo "</td></tr>"; 
   } 
   
   echo "</table>";
   }
   if (isset($_GET['hello'])) {
      runMyFunction();
   }
   ?>
   

   Run PHP Function

What should i do to populate my variable with the selected item from drop-down list?