Sending Ajax requests and updating DOM
I personally like to rely on named functions rather than inline anonymous functions.

this.AjaxPoller = {
  poll: poll,
  request: request
};

function request() {
  $(".ajax_poller[data-url]").each(fetchDataForElement);
}

function fetchDataForElement(i, elem) {
  var url = $(elem).data("url");
  $.getJSON(url, handleJson);
}

function handleJson(data) {
  if (checkProgress(data)) {
    location.reload();
  }
  $.each(data, function(key, val) {
    $(key+ ' .progress_info').html(val);
    $(key + ' .progress-bar').width(val);
  });
}

function poll() {
  setTimeout(this.request, 5000); 
}

function checkProgress(obj) {
  var correct = true;
  for (key in obj) {
    if (obj[key] != '100%') correct = false;
  }
  return correct;
}