Slideshow by array using slice method
JavaScript does type conversion automatically, there is no need to create the myArray variable. You can do that entire bit using a for loop similar to this:

var showArray = function (num) {
  $('.info').empty();
  for (var i = num; i &lt; Math.max(num + 5, 13); ++i) {
    $('.info').append(`&lt;h1&gt;${n}&lt;/h1&gt;`);
  }
};


(Maybe instead of hardcoding 13, you have a const for the length)
Keep your use of semicolons consistent. Either have them or don't. Pick a style convention and stick to it.