jquery select parent and then childrens

<script>
jQuery( document ).ready(function() {
    jQuery('.more, .lessbutton').hide();
    jQuery('.postbox').on('click', '.morebutton', function(){
         jQuery(this).closest('.postbox').children('.postcontent').children('.less').hide();
         jQuery(this).closest('.postbox').children('.buttons').children('.morebutton').hide();
         jQuery(this).closest('.postbox').children('.postcontent').children('.more').show();
         jQuery(this).closest('.postbox').children('.buttons').children('.lessbutton').show();
    });
    jQuery('.postbox').on('click', '.lessbutton', function(){
         jQuery(this).closest('.postbox').children('.postcontent').children('.less').show();
         jQuery(this).closest('.postbox').children('.buttons').children('.morebutton').show();
         jQuery(this).closest('.postbox').children('.postcontent').children('.more').hide();
         jQuery(this).closest('.postbox').children('.buttons').children('.lessbutton').hide();
    });
});
</script>