<script type="text/javascript">
$(document).ready(function(){
    $('.subLink').click(function(){
      $(this).parent().children('div.subCont').toggle('normal');
      if( $(this).attr("value")=='Открыть' ) $(this).attr("value","Закрыть");
      else $(this).attr("value","Открыть");
      return false;
    });
  });
</script>

<div><input class="subLink" type="button" value="Открыть">
<div style="display:none;position:absolute;" class="subCont">
содержимое
</div></div>

<style>
.subCont{
display:none;
border:1px solid #000;
padding:5px;
}
</style>

<script type="text/javascript">
var mr = document.getElementById("main-reply"); var inp; var i = 0; var edit;
var f;
var reg = new RegExp("\\[edit\\](.[^\\[]+)\\[/edit\\]");

function make_field() {
 var field = document.createElement("input");
 field.id = "field_edit";
 field.type = "text";
 field.size = "80";
 field.style.marginTop = "15px";
 mr.parentNode.appendChild(field);
}

function make_text() {
 var mrv_new; var fv; var mrv;
 fv = f.value;
 mrv = mr.value;
 if (mrv.indexOf("[edit]") == -1) {
  if (fv != "") mr.value += "\n[edit]" + fv + "[/edit]";
  else {}
 } 
 else {
  if (fv != "") mrv_new = mrv.replace(reg, "\n[edit]" + fv + "[/edit]");
  else mrv_new = mrv.replace(reg, "");
  mr.value = mrv_new;
 }
}

function check(x) {
 if (x.checked == false) f.disabled = false;
 if (x.checked == true) {
  f.disabled = true;
  f.value = "";
  mr.value = mr.value.replace(reg, "");
  f.setAttribute("placeholder", "Укажите причину редактирования");
 }
}

function make_description() {
 var post; var j = 0; var p; var z = 0;
 post = document.getElementById("pun-main").getElementsByTagName("div");
 for (j in post) {
  if (post[j].className == "post-content") {
   p = post[j].getElementsByTagName("p");
   for (z in p) {
    if ((p[z].className == "lastedit") && (reg.test(post[j].innerHTML))) {
     edit = post[j].innerHTML.match(reg)[0];
     edit = edit.substr(edit.indexOf("[edit]") + 6, edit.indexOf("[/edit]") - 6);
     p[z].innerHTML += "<span class='edit_text'>, <b>Причина:</b> " + edit + ".</span>";
     post[j].innerHTML = post[j].innerHTML.replace(reg, "");
    }
    else {}
   }
  }
 }
}

if (document.URL.indexOf("edit.php") != -1) {
 make_field();
 f = document.getElementById("field_edit");
 if (reg.test(mr.value)) {
  edit = mr.value.match(reg)[0];
  edit = edit.substr(edit.indexOf("[edit]") + 6, edit.indexOf("[/edit]") - 6);
  f.value = edit;
 }
 else f.setAttribute("placeholder", "Укажите причину редактирования");
 inp = document.getElementById("pun-main").getElementsByTagName("input");
 for (i in inp) {
  if (inp[i].value == "Отправить") inp[i].setAttribute("onclick", "make_text();");
  else if (inp[i].type == "checkbox") {
   inp[i].checked = false;
   inp[i].setAttribute("onclick", "check(this);");
  }
 }
}
if (document.URL.indexOf("viewtopic.php") != -1) make_description();
</script>