How do I make my dropdowns depended within a JQuery Modal Dialog box.

Is it possible to have depended drop down lists within a JQuery Dialog box such that when I pick value in the first drop down lists it changes the available values in the second list.
In my example the first list is a new project, when this is changed the accommodation changes to reflect those associated with the project.

I was trying to use autosubmit() within my dialogue box to refresh the depended drop down list but this submits the dialogue and the window closes.

The function which creates the modal is:

$(function() {

    $( "#addTicket" ).click(function() {

      var id = $(this).attr("file-id");
        var dataString =  id;

            $.ajax({
                type: "POST",
                url: "create_ticket.php",
                data: dataString,
                cache: false,
                success: function(data) {
                    $("#add-window").dialog(
                        {
                        autoOpen: true,
                        maxWidth:650,
                        maxHeight: 600,
                        width: 650,
                        height: 600,
                        draggable: true,
                        modal: true,
                        buttons: {
                          "Save": function () 
                          { 
                          $.post("create_ticket_process.php", $("#addForm").serialize(), function(response)
                            {
                            if(!response)
                            {
                            location.reload(true);
                            }
                            $("p#errors").html(response);            
                            });
                          $(this).dialog("destroy");
                         },
                          "Cancel": function () 
                            {
                            $(this).dialog("destroy");
                            }
                        } 
                    });
                  $("#addFormBody").html(data);
                }
            });

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The section of the form (create_ticket.php) which has the depended drop downs and is loaded into the modal dialog box is:

</tr>
	<tr>
	<td><select name="project" onChange="autoSubmit();">        
        <option value=null></option>';
        
        
        //POPULATE DROP DOWN MENU WITH PROJECTS
        
        $sql1 = "SELECT project_name FROM project WHERE end_date IS NULL ;" ;
        $projects = mysqli_query($dbci, $sql1);
        
        while($row3 = mysqli_fetch_array($projects))
        {        
            echo ("<option value=\"$row3[project_name]\" " . ($project == $row3["project_name"] ? " selected" : "") . ">$row3[project_name]</option>");        
        }
        
echo '
        
    </select></td>
	</tr>
	<tr>
	<td><select name="accommodation" onChange="autoSubmit();">        
        <option value=null></option>';
        
        
        //POPULATE DROP DOWN MENU WITH ACCOMMODATION
        
        $sql2 = "SELECT site_name  FROM accommodation WHERE project = $project;" ;
        $properties = mysqli_query($dbci, $sql4);
        
        while($row4 = mysqli_fetch_array($properties))
        {        
            echo ("<option value=\"$row4[site_name]\" " . ($hostel == $row4["site_name"] ? " selected" : "") . ">$row4[site_name]</option>");        
        
        }
        
echo '
        
    </select></td>
	</tr>

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Any pointers or examples would be gratefully received.
Thanks