Block users in their comments by pressing right mouse button.

facebook-instant-block-user.js

// ==UserScript==
// @name         Facebook Instant Block User
// @namespace    http://tampermonkey.net/
// @version      1.0.0
// @description  try to take over the world!
// @author       You
// @match        https://www.facebook.com*
// @grant        none
// ==/UserScript==

(function () {
  setInterval(addBehavior, 5000)

  document.body.addEventListener('click', hideContextMenus)

  function addBehavior() {
    const comments = document.querySelectorAll('._72vr:not(._blockinit)')

    comments.forEach(comment => addContextMenu(comment))
  }

  function addContextMenu(comment) {
    comment.addEventListener('contextmenu', function (e) {
      e.preventDefault()

      showContextMenu(e.pageX, e.pageY, comment)
    })

    comment.classList.add('_blockinit')
  }

  function showContextMenu(x, y, comment) {
    hideContextMenus()

    const ul = document.createElement('ul')
    const items = []

    items.push({
      label: 'Instant block user',
      onclick: e => handleBlockUser(comment)
    })

    items.push({
      label: 'Cancel',
      onclick: hideContextMenus
    })

    items.forEach(item => {
      const li = document.createElement('li')

      li.textContent = item.label
      li.onclick = item.onclick
      li.style.padding = '20px'
      li.style.cursor = 'pointer'
      li.style.fontSize = '14px'

      li.addEventListener('mouseenter', e => {
        li.style.backgroundColor = '#f2f2f2'
      })

      li.addEventListener('mouseleave', e => {
        li.style.backgroundColor = 'white'
      })

      ul.appendChild(li)
    })

    ul.style.backgroundColor = 'white'
    ul.style.color = 'black'
    ul.style.listStyle = 'none'
    ul.style.boxShadow = '0 3px 6px 1px rgba(0, 0, 0, .5)'
    ul.style.position = 'absolute'
    ul.style.left = x + 'px'
    ul.style.top = y + 'px'
    ul.style.zIndex = '1'
    ul.className = '_blockuser_dropdown'
    ul.onclick = e => e.stopPropagation()

    document.body.appendChild(ul)
  }

  function hideContextMenus() {
    document.querySelectorAll('._blockuser_dropdown')
      .forEach(contextmenu => contextmenu.remove())
  }

  function handleBlockUser(comment) {
    if (window.confirm('Are you sure you want to block this user?')) {
      const hovercard = comment.querySelector('a').dataset.hovercard
      const profile_id = hovercard.split('?id=')[1]
      const fb_dtsg = document.querySelector('input[name="fb_dtsg"]').value
      const fd = new FormData()

      fd.append('uid', profile_id)
      fd.append('confirmed', '1')
      fd.append('fb_dtsg', fb_dtsg)

      fetch('https://www.facebook.com/ajax/privacy/block_user.php', {
        method: 'POST',
        body: fd
      })

      hideContextMenus()

      comment.closest('li').remove()
    }
  }
  
  addBehavior()
})()