ask-fm-mandatory-registration-removal.userscript.js

// ==UserScript==
// @name        Ask.fm mandatory registration removal
// @description Removes the mandatory registration requirement from Ask.fm
// @version     1.0
// @include     https://ask.fm/*
// ==/UserScript==

(() => {
  const observer = new MutationObserver((mutations) => {
    for (const mutation of mutations) {
      for (const node of mutation.addedNodes) {
        if (node.classList.contains('lightbox_overlay')) {
          document.body.removeChild(node);
          document.body.classList.remove('lightbox-open');
        }
      }
    }
  });
  
  observer.observe(document.body, { childList: true });
})();