HTML
<input type="text" name="search" id="search" placeholder="Быстрый поиск ...">
<ul>
<?php query_posts('posts_per_page=-1');?>
<?php if ( have_posts() ) : ?>
<?php while ( have_posts()) : the_post(); ?>
<li class="list-news--inner">
<a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
</li>
<?php endwhile; ?>
<?php endif; ?>
<?php wp_reset_query();?>
</ul>
Jquery
(function(){
$(document).ready(function() {
$('#search').keyup(function(event) {
if (event.keyCode == 27 || $(this).val() == '') {
$(this).val('');
$('.list-news--inner').removeClass('name').show().addClass('name');
}
else {
filter('.list-news--inner', $(this).val());
}
});
});
function filter(filter, query) {
query = $.trim(query);
$(filter).each(function() {
($(this).text().search(new RegExp(query, "i")) < 0) ? $(this).hide().removeClass('name') :
$(this).show().addClass('name');
});
}
})();