JSFiddle - React, Tailwind, and code Playground

HTML

<button id="mango" >Load More</button>

JavaScript

var maxnumId = null,
    counteri= null,
    totali =null;
    
function callApi() {
    $.ajax({
        type: "GET",
        dataType: "jsonp",
        cache: false,
        // change this with your url
        url: "//jsfiddle.net/echo/jsonp/",
        success: function(data) {
            var i;
            // because i cannot reproduce your response ajax i commented this
            //maxnumId = data['pagination[next_num_id]'];
            for (i = 0; i < 100; i++) {
                // because i cannot reproduce your response ajax i commented this
                // document.myform.outputtext.value = document.myform.outputtext.value+data.data[i].images.ok.url+'\n' ; 
            }
            counteri = i;
            totali = totali +i;     
            alert('counteri is now: ' + totali);
        }
    });
}

$("#mango").on("click",function(){
    callApi();
});