How to use AJAX to create/update radio buttons?

I currently have a setup where I use a PHP script to create a list of radio buttons by loading the required information from my database. This script is in the HTML structure rather than a separate file, so it requires a page refresh to update the list.

I'd like to figure out how to delete and reload the list upon pressing a button, the ID of which is 'btnDelete' (the actual deletion of items in the database is a separate point that I won't go into here). The current code that I have will delete the list of radio buttons, but when the next line is added, nothing happens (including list deletion).

PHP (delCom.php)

                <?php
                    include_once('includes/conn.inc.php');
                    $query = ("SELECT comicID, comicName  FROM comic WHERE username = '".$_SESSION['username']."'");
                    $result = mysqli_query($conn, $query);
                    while ($row = $result->fetch_assoc()) 
                    {
                        echo "<br><input name='comicList' id='".$row['comicID']."' type='radio' value='".$row['comicID']."'>".$row['comicName']."  </option>";
                    }
                ?>

JavaScript

function delComic()
        {
            var ajaxRequest;  

            try
            {
                // Opera 8.0+, Firefox, Safari
                ajaxRequest = new XMLHttpRequest();
            } 
            catch (e)
            {
                // Internet Explorer Browsers
                try
                {
                    ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
                } 
                catch (e) 
                {
                    try
                    {
                        ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
                    } 
                    catch (e)
                    {
                        // Something went wrong
                        alert("Your browser broke!");
                        return false;
                    }
                }
            }
            // Create a function that will receive data sent from the server
            ajaxRequest.onreadystatechange = function()
            {
                if(ajaxRequest.readyState == 4)
                {
                    $("#loadList").remove();
                    document.getElementById("divComics").innerHTML=xmlhttp.responseText;
                }
            }
            ajaxRequest.open("GET", "delCom.php?t=", true);
            ajaxRequest.send(null); 

        }

HTML

<div id="divComics">
            <p><u>Uploaded Comics</u></p>
            <!-- find comics in database -->
            <div id="loadList">
                <?php
                    include_once('includes/conn.inc.php');
                    $query = ("SELECT comicID, comicName  FROM comic WHERE username = '".$_SESSION['username']."' ORDER BY comicName ASC");
                    $result = mysqli_query($conn, $query);
                    while ($row = $result->fetch_assoc()) 
                    {
                        echo "<br><input name='comicList' id='".$row['comicID']."' type='radio' value='".$row['comicID']."'>".$row['comicName']."  </option>";
                    }
                ?>
            </div>
            <br>
            <br>
            <input  type="button" onclick="delComic()" value="Delete Comic" name="deleteButton" id="btnDelete"/>
        </div>

The code creates buttons correctly when run in the HTML, but not when in a separate php file.

Thanks in advance.

EDIT: Updated to fix a few misnamed things. Also, the 'loadList' div needs to be recreated after deletion in the PHP, which I'm not sure how to do. This needs doing because I cannot find a way to delete the list of buttons by themselves.