function doAjaxRequest(pars, div, callback) {
  jQuery.ajax({
    type: "POST",
    url: "?",
    data: pars,
    success: callback
  });
}

function validateEmail(elementValue) {
  var emailPattern = /^([a-zA-Z0-9_.-])+@([a-zA-Z0-9_.-])+\.([a-zA-Z])+([a-zA-Z])+/;
  return emailPattern.test(elementValue);
}