Post counter

post_counter.php

/////////////// IN FUNCTION.PHP ///////////////

function wpb_set_post_views($postID) {
    $count_key = 'wpb_post_views_count';
    $count = get_post_meta($postID, $count_key, true);
    if($count==''){
        $count = 0;
        delete_post_meta($postID, $count_key);
        add_post_meta($postID, $count_key, '0');
    }else{
        $count++;
        update_post_meta($postID, $count_key, $count);
    }
}
//To keep the count accurate, lets get rid of prefetching
remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head', 10, 0);

/////////////// INSERT CODE BELOW TO TEMPLATE TO INITIALIZE COUNTING ///////////////

wpb_set_post_views(get_the_ID());


/////////////// WIDGET ///////////////


<?php
    $popularpost = new WP_Query( array( 'post_type' => array('page','post'), 'posts_per_page' => 5, 'meta_key' => 'wpb_post_views_count', 'orderby' => 'meta_value_num', 'order' => 'DESC'  ) );
    while ( $popularpost->have_posts() ) : $popularpost->the_post();?>

    <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>

<?php endwhile;?>