WordPressにスライダーを実装したのですが、next、prevがうまく動作しません。

JavaScript
1jQuery(function($) {
2    jQuery('#slides').append('<ul id="pager"><li><a href="#" class="prev">＜</a></li><li><a href="#" class="next">＞</a></li></ul>');
3    var pager = jQuery('#pager'),
4        slidesWrap = jQuery('#slides'),
5        slides = jQuery('#slides-inner'),
6        slideKiji = slides.find('.slidekiji'),
7        slidenav = jQuery('#slides-nav'),
8        current = 0,
9        number = slideKiji.length;
10   
11    slideKiji.each(function(i) {
12        jQuery(this).css({
13            left: '100' * i + '%'
14        });
15        slidenav.append('<a href="#"></a>');
16    });
17   
18    function navUpdate() {
19        slidenav.find('a').removeClass('active');
20        slidenav.find('a').eq(current).addClass('active');
21    }
22   
23    function slider(index) {
24        if (index < 0) {
25            index = number - 1;
26        }
27        if (index > number - 1) {
28            index = 0;
29        }
30        slides.animate({
31            left: '-100' * index + '%'
32        });
33        current = index;
34        navUpdate();
35    }
36   
37    pager.find('a').click(function(event) {
38        event.preventDefault();
39        if (jQuery(this).hasClass('prev')) {
40            slider(current - 1);
41        } else {
42            slider(current + 1);
43        }
44    });
45   
46    slidenav.find('a').click(function(event) {
47        event.preventDefault();
48        var navIndex = jQuery(this).index();
49        navUpdate();
50        slider(navIndex);
51    });
52   
53    var start;
54   
55    function timerStart() {
56        start = setInterval(function() {
57            slider(current + 1);
58        }, 5000);
59    }
60   
61    function timerStop() {
62        clearInterval(start);
63    }
64   
65    slider(current);
66   
67    timerStart();
68   
69    slideKiji.on({
70        mouseover: timerStop,
71        mouseout: timerStart
72    });
73  });
74

すべてのコード

php
1<div id="slider-area">
2  <div id="slides" class="slides">
3    <div id="slides-inner" class="slides-inner">
4      <?php $args = array(
5      'posts_per_page' => 5,
6        );
7        $my_query = new WP_Query( $args );?>
8        <?php while ( $my_query->have_posts() ) : $my_query->the_post(); ?>
9 
10      <article <?php post_class( 'slidekiji' ); ?>>
11        <a href="<?php the_permalink(); ?>">
12          <?php the_post_thumbnail('large'); ?>
13          <div class="text">
14            <span class="kiji-date">
15              <time
16               datetime="<?php echo get_the_date( 'Y-m-d' ); ?>">
17              <?php echo get_the_date(); ?>
18               </time>
19            </span>
20            <span class="cat-data ">
21               <?php if( has_category() ): ?>
22                <?php $postcat=get_the_category(); echo $postcat[0]->name; ?>
23              <?php endif; ?>
24            </span>
25            <h2><?php the_title(); ?></h2>
26          </div>
27        </a>
28      </article>
29 
30      <?php endwhile; ?>
31      <?php wp_reset_postdata(); ?>
32    </div>
33  </div>
34  <div id="slides-nav" class="slides-nav"></div>
35</div>
36