swapFrame_example.user.js

// ==UserScript==
// @name     AliLogin
// @version  1
// @include	 https://login.aliexpress.com/*
// @grant    none
// ==/UserScript==

function swapFrame(frameId){
  let frameEl = document.getElementById(frameId);
  if (frameEl!=null ) {
    // Create <embed> and copy all attributes
    let embedEl = document.createElement('embed');
    for (var att, i = 0, atts = frameEl.attributes, n = atts.length; i < n; i++){
      att = atts[i];
      embedEl.setAttribute(att.nodeName,att.nodeValue);
    }
    // Perform the actual swap
    frameEl.parentElement.replaceChild(embedEl,frameEl); 
    console.log("GM: swapped iframe for embed.");
  } else { setTimeout(swapFrame, 100, frameId);} // Recursively run until the iframe has loaded
}

swapFrame('alibaba-login-box');