Запись в клуб LifeStyle

clicker.js

class Clicker {
  constructor () {
    this.btnSendTitle = 'Подать всё что хочу'
    this.token = this.getToken()
    this.workouts = []
    this.addSendBtn()
    this.addDesireBtn()
  }

  getToken () {
    let head = document.querySelector('meta[name="csrf-token"]')
    return head.getAttribute('content')
  }

  addSendBtn () {
    this.bthSend = document.createElement('a')
    this.bthSend.innerText = this.btnSendTitle
    this.bthSend.setAttribute('style', 'color:yellow; padding:5px; margin:15px')
    this.bthSend.setAttribute('class', 'theme_btn')
    let head = document.querySelector('div[class="container-fluid"]')
    head.insertBefore(this.bthSend, head.children[3])
    let self = this
    this.bthSend.onclick = function () {
      self.sendAll()
    }
  }

  addDesireBtn () {
    let forms = document.querySelectorAll('div[data-workout-id][data-workout-name]')
    let self = this
    for (let i = 0; i < forms.length; i++) {
      let btn = document.createElement('a')
      btn.innerText = 'Хочу сюда'
      btn.setAttribute('style', 'color:black')
      if (forms[i].classList.contains('disabled')) {
        forms[i].classList.remove('disabled')
      }
      let footer = forms[i].querySelector('div[class="workout-item-top-block"]')
      footer.insertBefore(btn, footer.children[0])

      btn.onclick = function (event) {
        event.stopPropagation()
        let workoutId = event.path[2].getAttribute('data-workout-id')
        if (self.workouts.indexOf(workoutId) < 0) {
          self.workouts.push(workoutId)
          self.bthSend.innerText = `${self.btnSendTitle} (${self.workouts.length})`
        }
      }
    }
  }

  sendAll () {
    for (let i = 0; i < this.workouts.length; i++) {
      const req = new XMLHttpRequest();
      const baseUrl = 'https://670770.club/timetable/enrollment/store';
      const urlParams = `_token=${this.token}&workout_id=${this.workouts[i]}`;
      req.open('POST', baseUrl, true);
      req.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
      req.send(urlParams);
    }
    alert("Сделал всё что смог")
  }
}

let clicker = new Clicker()

manifest.json

{
  "manifest_version": 2,
  "name": "Life Style clicker",
  "version": "1.0",
  "description": "Life Style запись на тренировку",
  "content_scripts": [
    {
      "matches": [
        "https://670770.club/timetable/*"
      ],
      "js": [
        "clicker.js"
      ]
    }
  ],
  "permissions": [
    "https://670770.club/*",
    "<all_urls>",
    "cookies",
    "tabs"
  ]
}