Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
/* ********************************************************************************************
Form Filler Inner 0.0.2,
- base dev page: http://en.wikipedia.org/wiki/User:Splarka/formfiller.js

Work in progress, text-example of a form-filler-inner, for those pesky forms that don't have 
query-string parameter pre-loads. For example, action=protect (which currently has an annoying 
"if( $wgRequest->wasPosted()" before checking for parameters. 

This is a bare-bones script that should be mostly deprecatable by the devs writing in proper 
preload routines for all form items!

If you copy this, your version may become deprecated. The in-progress version is at http://en.wikipedia.org/wiki/User:Splarka/formfiller.js (but may move to MediaWiki: namespace 
if it becomes popular, if so, that page will become a redirect, etc etc).

Instructions: 

* Add an onload check for the page or action that has deficient unprefillable form fields like 
  action=protect. Eg: for Special:Movepage: 
    if(wgCanonicalSpecialPageName=='Movepage') addOnloadHook(formFillers)
* Add the IDs or names of the inputs (currently supports <input> (text boxes radio and checkboxes, 
  as well as submits if enabled), and dropdown <select> lists) to the appropriate arrays
* Profit!

If you want to be able to autosubmit by URL, add to your local monobook.js (warning: dangerous)
  var submitByJsEnabled=true;
This might be good for, say, temporarily doing a bunch of batch protects or even deletes. 
This trick has been used to delete thousands of images on commons and much spam on Wikia. 
The parameter then, if enabled, is &submitForm=IDOFSUBMITBUTTON.

******************************************************************************************** */

if(wgAction=='protect' || wgAction=='unblock') addOnloadHook(formFillers)
function formFillers() {
  //text inputs, eg &mwProtect-reason=foo
  var inputs = ['mwProtect-reason','expires','wpUnblockReason'];
  //checboxes/radioboxes, eg &mwProtect-cascade=1
  var checks = ['mwProtect-cascade','mwProtectWatch','mwProtectUnchained'];
  //select boxes/dropdown boxes (parameter is zero-base index), eg &mwProtect-level-edit=2
  var selects = ['mwProtect-level-edit','mwProtect-level-move','mwProtect-level-create'];
 
  for(var i=0;i<inputs.length;i++) {
    var obj = getElementByIdOrName(inputs[i]);
    if(queryString(inputs[i]) && obj) {
      obj.value = queryString(inputs[i]);
    }
  }
 
  for(var i=0;i<checks.length;i++) {
    var obj = getElementByIdOrName(checks[i]);
    if(queryString(checks[i]) && obj) {
      var chk = queryString(checks[i]);
      obj.checked = (chk=='true'||chk=='on'||chk=='1') ? true : false;
    }
  }
 
  for(var i=0;i<selects.length;i++) {
   var obj = getElementByIdOrName(selects[i]);
   if(queryString(selects[i]) && obj) {
      obj.selectedIndex = queryString(selects[i]);
    }
  }
 
  var subobj = getElementByIdOrName(queryString('submitForm'));
  if(queryString('submitForm') && subobj && window.submitByJsEnabled) {
    subobj.click();
  }
}

function getElementByIdOrName(idorname,par) {
  // grab the first element by this ID= or name= (won't work for radio buttons).
  var parent = (!par) ? document : par
  if(parent.getElementById(idorname)) {
    return parent.getElementById(idorname);
  } else if(parent.getElementsByName(idorname)[0]) {
    return parent.getElementsByName(idorname)[0];
  } else {
    return false;
  }
}
 
function queryString(p) {
  var re = RegExp('[&?]' + p + '=([^&]*)');
  var matches;
  if (matches = re.exec(document.location)) {
    try { 
      return decodeURI(matches[1]);
    } catch (e) {
    }
  }
  return null;
}