BBS Formatting Options

// ==UserScript==
// @name             Show BBS Format Options
// @namespace        dollars-bbs.org
// @author           Degritone
// @description      Shows the formatting options when making a new post
// @match            *://*.dollars-bbs.org/*
// @grant            none
// ==/UserScript==

function work(loaded){
  let threadlinks = document.getElementsByClassName("threadlinks");
  if(threadlinks.length<1){
    setTimeout(work,100,false);
    return;
  }
  if(!loaded){
    setTimeout(work,1000,true);
    return;
  }
  let newposts = [];
  for(let i=0;i<threadlinks.length;i++){
    let a = 0;
    if(window.location.href.includes("/res/"))
      a++;
    newposts[i] = threadlinks[i].getElementsByTagName("a")[a];
  }
  for(let i=0;i<newposts.length;i++){
    if(newposts[i]){
      let threadNumber = newposts[i].href.match(/reply[0-9]+/)[0].replace("reply","");
      newposts[i].href = newposts[i].href+" show('options"+threadNumber+"');"
      document.getElementById("preview"+threadNumber).style.color = "#FFFFFF";
    }
  }

  if(document.getElementById("createbox")){
    let newthread = document.getElementById("createbox").getElementsByClassName("innerbox")[0].getElementsByTagName("a")[0];
    newthread.href = newthread.href+" show('options');";
    document.getElementById("preview").style.color = "#FFFFFF";
  }

  let options = document.getElementsByTagName("option");
  for(let i=2;i<options.length;i+=4){
    options[i].outerHTML = "<option value='html' selected>HTML</option>";
    options[i].parentNode.onchange();
  }

  window.preview_post = function(formid,thread){
    let form=document.getElementById(formid);
    let preview=document.getElementById("preview"+thread);

    if(!form||!preview) return;

    preview.style.display="";
    preview.innerHTML="<em>Loading...</em>";
    let text;
    text="task=preview";
    text+="&comment="+encodeURIComponent(form.comment.value);
    text+="&markup="+encodeURIComponent(form.markup.value);
    if(thread) text+="&thread="+thread;

    let xmlhttp=get_xmlhttp();
    xmlhttp.open("POST",window.location.href.match(/\.org\/.+?\//)[0].replace(".org","").replace("/","")+"/kareha.pl");
    xmlhttp.onreadystatechange=function() {
      if(xmlhttp.readyState==4) preview.innerHTML=xmlhttp.responseText;
    }
    if(is_ie()||xmlhttp.setRequestHeader) xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
    xmlhttp.send(text);
  }
}

work(false);