pagination

function getUrlParameter(url, parameter) {
  parameter = parameter.replace(/[\[]/, '\\[').replace(/[\]]/, '\\]');
  var regex = new RegExp('[\\?|&]' + parameter.toLowerCase() + '=([^&#]*)');
  var results = regex.exec('?' + url.toLowerCase().split('?')[1]);
  return results === null ? '' : decodeURIComponent(results[1].replace(/\+/g, ' '));
}

function setUrlParameter(url, key, value) {

  var baseUrl = url.split('?')[0],
    urlQueryString = '?' + url.split('?')[1],
    newParam = key + '=' + value,
    params = '?' + newParam;

  // If the "search" string exists, then build params from it
  if (urlQueryString) {
    var updateRegex = new RegExp('([\?&])' + key + '[^&]*');
    var removeRegex = new RegExp('([\?&])' + key + '=[^&;]+[&;]?');

    if (typeof value === 'undefined' || value === null || value === '') { // Remove param if value is empty
      params = urlQueryString.replace(removeRegex, "$1");
      params = params.replace(/[&;]$/, "");

    } else if (urlQueryString.match(updateRegex) !== null) { // If param exists already, update it
      params = urlQueryString.replace(updateRegex, "$1" + newParam);

    } else { // Otherwise, add it to end of query string
      params = urlQueryString + '&' + newParam;
    }
  }

  // no parameter was set so we don't need the question mark
  params = params === '?' ? '' : params;

  return baseUrl + params;
}