Select option reload and change value of other select box

Question

I have two select boxes.

Select Room Type
Select Room No.

Here is the php code:

<select id="room_type" name="room_type"  class="form-control">
<?php
$selected = $row['room_type'];
while($result = mysqli_fetch_array($getroomtypes)){ ?>
<option value="<?php echo $result['id'];?>" > <?php echo $result['type'];?> </option>
<?php
}
?>
</select></div>
</div>

<div class="form-group">
<label  class="control-label col-sm-2">Select Room</label>
<div class="col-sm-5">
<select id="room" name="room"  class="form-control">
<?php
$selected = $row['room'];
while($result = mysqli_fetch_array($getroom)){ ?>
<option value="<?php echo $result['id'];?>"> <?php echo $result['room'];?> </option>
<?php
}
?>
</select></div>
</div>

So the issue here is Room No. depends on room type. For every room type there are various room numbers. Can anyone suggest me how can i reload the values of room no after selecting the room type?

I am using bootstrap.

Answer 1

You'll need to use JS for reloading room numbers, the way I would do (by no means the best way) is to have a script (mine below uses jQuery), this is faster than fetching the value from a DB but less safe:

$('#room_type').on('change', function(e){ // when the room_type changes
  $('#room').remove('option');  // remove all previous options

  let maxRooms = e.val() == "Shit Muncher Suite" ? 3 : 0; // set max rooms depending on room_type, e.val() is the room_type

  for(var i = 0; i < maxRooms; i++) {
   $('#room').add("option").text(i); // add a new option for each room (3) 
  }

}); 

Answer 2

If you want potential data from the database to load without your page refreshing, you have to use AJAX. PHP cannot load new data without refreshing the entire page. Hoped I helped :)