Provo a postare script completo, grazie
codice:
<script type="text/javascript" >

jQuery(document).ready(function() {
    //populate_home_posts(4);


    
    jQuery('#menuCategoryNews li').click(function(){
    jQuery('#menuCategoryNews li').removeClass('currentCat');
        jQuery(this).addClass('currentCat');
        populate_home_posts(jQuery(this).data('id'));
    });    
    
    jQuery('#menuCategoryNews li:nth-child(1)').trigger('click');   
    setInterval(function() { 
        if(jQuery('#mainNewsImage div').length > 1)
          jQuery('#mainNewsImage > div:nth-child(1)')
            .fadeOut(1000)
            .next()
            .fadeIn(1000)
            .end()
            .appendTo('#mainNewsImage');
    },  8000);
});



function populate_home_posts(cat){
    
    var ajaxurl = '/wp-admin/admin-ajax.php';
    
    var data = {
        action: 'home_posts',
        cat: cat
    };
    
    jQuery('#mainNewsImage').html('<div class="loading">Loading...</div>');
    jQuery('#primaryNews .entry-title').html('');
    jQuery('#primaryNews .entry-content').html('');
    jQuery('#secondaryNews1 .secondaryNewsImage').html('<div class="loading">Loading...</div>');
    jQuery('#secondaryNews1 .entry-title').html('');
    jQuery('#secondaryNews1 .entry-content').html('');
    jQuery('#secondaryNews2 .secondaryNewsImage').html('<div class="loading">Loading...</div>');
    jQuery('#secondaryNews2 .entry-title').html('');
    jQuery('#secondaryNews2 .entry-content').html('');

    jQuery.post(ajaxurl, data, function(response) {
       
        jQuery('#mainNewsImage').html('');
        jQuery('#primaryNews .entry-title').html('');
        jQuery('#secondaryNews1 .secondaryNewsImage').html('');
        jQuery('#secondaryNews1 .entry-title').html('');
        jQuery('#secondaryNews2 .secondaryNewsImage').html('');
        jQuery('#secondaryNews2 .entry-title').html('');
    
        jQuery.each(response, function(i, item){
          switch(i){
            case 0:
                if(item.thumbnail){
                    var imgContent = '<div><a href="'+item.permalink+'"><img src="'+item.thumbnail+'" title="'+item.title+'" alt="'+item.title+'" /></a></div>';
                    
                    for(var g in item.gallery){
                        imgContent += '<div style="display:none"><a href="'+item.permalink+'"><img src="'+item.gallery[g][0]+'" title="'+item.title+'" alt="'+item.title+'" /></a></div>';
                    }
                    
                    jQuery('#mainNewsImage').html(imgContent);
                }
                jQuery('#primaryNews .entry-title').html('<a href="'+item.permalink+'">'+item.title+'</a>');
                jQuery('#primaryNews .entry-content').html(item.excerpt);
            break;
            
            case 1:
                if(item.thumbnail)
                    jQuery('#secondaryNews1 .secondaryNewsImage').html('<a href="'+item.permalink+'"><img src="'+item.thumbnail2+'" title="'+item.title+'" alt="'+item.title+'" /></a>');
                
                jQuery('#secondaryNews1 .entry-title').html('<a href="'+item.permalink+'">'+item.title+'</a>');
                jQuery('#secondaryNews1 .entry-content').html(item.excerpt);
            break;
            
            case 2:
                if(item.thumbnail)
                    jQuery('#secondaryNews2 .secondaryNewsImage').html('<a href="'+item.permalink+'"><img src="'+item.thumbnail2+'" title="'+item.title+'" alt="'+item.title+'" /></a>');
                
                jQuery('#secondaryNews2 .entry-title').html('<a href="'+item.permalink+'">'+item.title+'</a>');
                jQuery('#secondaryNews2 .entry-content').html(item.excerpt);
            break;
          }
          
          //console.log(item.title);
        });
    });
}

</script>