Easy WordPress AJAX

default.js

//Ajax for filter (replace DOMAIN.com with your domain name)
$("#postFilterLinks a").click(function(e) {
    e.preventDefault();
    var dataID = $(this).attr("data-id")
    $.ajax({
        type: "GET",
        url: "http://DOMAIN.com/posts-filter",
        data: "categoryID="+dataID,
        success: function(html) {
            $("#postsFiltered").html(html);
        }
    });
});

template-homepage.php

<?php
/**
 * The template for displaying the homepage.
 *
 * Template name: Homepage
 *
 * @package
 */
get_header();
?>

<div id="postFilter">
                <div id="postFilterLinks">
                    <ul class="list-inline">
                        <li class="list-inline-item"><a class="filterLink" href="" data-id="0">All</a></li>
						<?php
						$categories = get_categories();
						foreach($categories as $category) {
							echo '<li class="list-inline-item"><a href="" data-id="'.$category->term_id.'">'.$category->name.'</a></li>';
						}
						?>
                    </ul>
                </div>

                <h2>Latest News</h2>
                <div id="postsFiltered">
					<?php
					$args = array(
						'post_type' => 'post',
						'posts_per_page' => -1,
					);
					$loop = new WP_Query( $args );
					while ( $loop->have_posts() ) : $loop->the_post(); ?>
                  <a id="id-<?php the_id(); ?>" href="<?php the_permalink(); ?>" title="<?php the_title(); ?>">
                      <h3><?php the_title(); ?></h3>
                  </a>
					<?php endwhile; ?>
					<?php wp_reset_query(); ?>
                </div>
            </div>
<?php get_footer(); ?>

template-postsFilter.php

<?php
/**
 * The template for displaying the Posts Filter. (make sure this pages url is posts-filter otherwise change it in the default.js
 *
 * Template name: Posts Filter
 *
 * @package 
 */
if(!empty($_GET['categoryID'])) {
	$categoryID = $_GET['categoryID'];
	$args = array(
		'cat' => $categoryID,
		'post_type' => 'post',
		'posts_per_page' => -1,
	);
} else{
	$args = array(
		'post_type' => 'post',
		'posts_per_page' => -1,
	);
}
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post(); ?>
    <a id="id-<?php the_id(); ?>" href="<?php the_permalink(); ?>" title="<?php the_title(); ?>">
        <h3><?php the_title(); ?></h3>
    </a>
<?php endwhile; ?>
<?php wp_reset_query(); ?>