WordPress AJAX Live Search of Post Title

form-content.html

<!-- // The HTML (could be part of page content) // -->
<input type="text" name="keyword" id="keyword" onkeyup="fetch()"></input>
<div id="datafetch">Search results will appear here</div>

functions.php

<?php

// add the ajax fetch js
add_action( 'wp_footer', 'ajax_fetch' );
function ajax_fetch() {
?>
<script type="text/javascript">
function fetch(){

    jQuery.ajax({
        url: '<?php echo admin_url('admin-ajax.php'); ?>',
        type: 'post',
        data: { action: 'data_fetch', keyword: jQuery('#keyword').val() },
        success: function(data) {
            jQuery('#datafetch').html( data );
        }
    });

}
</script>

<?php
}


// the ajax function
add_action('wp_ajax_data_fetch' , 'data_fetch');
add_action('wp_ajax_nopriv_data_fetch','data_fetch');
function data_fetch(){

    $the_query = new WP_Query( 
      array( 
        'posts_per_page' => -1, 
        's' => esc_attr( $_POST['keyword'] ), 
        'post_type' => 'post' 
      ) 
    );
  
    if( $the_query->have_posts() ) :
        while( $the_query->have_posts() ): $the_query->the_post(); ?>

            <h2><a href="<?php echo esc_url( post_permalink() ); ?>"><?php the_title();?></a></h2>

        <?php endwhile;
        wp_reset_postdata();  
    endif;

    die();
}

omment and

@KixKira It's because in that line, you're mixing php and html. Either change it to this:

            if(stripos("/{$search}/", $a) !== false) {  ?>
                <li><a href="<?php echo esc_url( post_permalink() ); ?>"><?php the_title();?></a></li>
            <?php }

or this:

            if(stripos("/{$search}/", $a) !== false) {              
                echo '<li><a href="'.esc_url( post_permalink() ).'">'.the_title().'</a></li>';
            }