How to make nextPage button in javascript?

I want to make nextPage, prevPage button like below

below is my code

function getYoutubeList(boardname, index) {                                                                                                                                      
  $.ajax({                                                                                                                                                                       
    url:"/" + boardname + "/" + index,                                                                                                                                     
    method:'GET',                                                                                                                                                                
    dataType:'json'                                                                                                                                                              
  }).done(function(json, textStatus){                                                                                                                                                                                                                
    $('.container').append($('<div>', {style:"position:absolute;", class:"page_container"}));                                                                                    
    $('.page_container').append($('<div>').append($('<button>', {id:"shf_prev_btn", onclick:"prevPage()"}).text("prev")));                                                         
    $('.page_container').append($('<div>').append($('<span>', {id:"shf_page", role:"button"}).text(index)));                                                                     
    $('.page_container').append($('<div>').append($('<button>', {id:"shf_next_btn", onclick:"nextPage()"}).text("next")));

I want to make like this if button is clicked, nextPage(), prevPage() is called then page index is changed if nextPage(), index + 1 if prevPage(), index -1

also, else opinion is okay, I just want to make nextPage, prevPage button.