Why does ajax return undefined?

Question

AJAX

There is a site - tyts

Below there is a button that loads the goods from page 2 with Ajax, the code is corny

var page = 1;
  $(document).on('click', '.show-more', function(e){
    e.preventDefault();
    page = page+1;
    
    $.ajax({
      type: 'GET',
      data:{'page':page},
      beforeSend: function(){
        $('.show-more').addClass('active');
      },
      success:function(data){
        content = $(data).find('.item_ajax');
        pagination = $(data).find('#pagination').html();
        console.log(content);
        console.log(pagination);
        setTimeout(function()
        {
          if(content.length>0)
          {
            $('#content').append(content);
            $('#pagination').html(pagination); 
            display($.totalStorage('display')); 
          }
          else
          {
            $('.show-more').html('<i class="fa fa-ban" aria-hidden="true"></i>Больше нет!');
            setTimeout(function()
            {
              $('.show-more').slideUp(350);
            }, 1600);
          }
          $('.show-more').removeClass('active');
        }, 700);
      }
    });
  });

Clicking on the button loads the next page.

Everything works fine on the standard template, but for some reason it returns.

e.fn.init [prevObject: e.fn.init(1), context: undefined, selector: '.item_ajax']

and
undefined

This is me logging

console.log(content);
        console.log(pagination);

The solution itself works, but some kind of conflict is created here, although #content , #pagination , .item_ajax are spelled correctly and in their places.