function setXCookie(n, v) {
  var d = new Date();
  d.setTime(d.getTime()+1000);

  var pn = escape(n);
  document.cookie = pn + "=" + escape(v) 
    + "; expires=" + d.toGMTString() + "; path=/";

}

function addReqHeaderParam(n, v) {
  setXCookie("X-Param-" + n, v);
}

function setReqVariantId(id) {
  setXCookie("X-Variant", id);
}