poc for rendering iframe with ajax exponential backoff retry strategy

retry.js

// <iframe id='iframe' frameborder='0' height='200' width='300'></iframe>

var frame = document.getElementById("iframe").contentWindow.document;

function retryTimeout(n, maximum_backoff) {
  maximum_backoff = (typeof maximum_backoff !== 'undefined') ?  maximum_backoff : 5000;
  if (n < 0) n = 0;
  if (maximum_backoff < 0) maximum_backoff = 5000;
  var time = 2**(n-1)*100 + Math.floor(Math.random()*100);
  
  return Math.min(time, maximum_backoff);
}

function callAjax(count) {
  count = (typeof count !== 'undefined') ?  count : 0
  $.ajax({
    url: count == 6 ? "https://httpstat.us/200/cors" : "https://httpstat.us/502/cors",
    retryLimit : 10,
    success: function(result){
      frame.open();
      frame.write(result);
      frame.close();
    },
    error : function(xhr, textStatus, errorThrown ) {
      if (count < this.retryLimit) {
        frame.open();
        frame.write(count);
        frame.close();
        ++count;
        setTimeout(function() {callAjax(count);}, retryTimeout(count));
        return;
      }            
      return;
    }
  });
}

callAjax();