Unity Forum Search : AutoSelect current board item inside Search select list (based on referrer url)

UnityForumBoardSearchHelper.js

// ==UserScript==
// @name     Unity Forum Search : AutoSelect current board item inside Search select list (based on referrer url)
// @namespace   https://unitycoder.com
// @version  1
// @include  https://forum.unity.com/search/?type=post
// @grant    none
// ==/UserScript==
// more info https://unitycoder.com/blog/2021/05/26/unity-forums-auto-select-current-subforum-in-search-greasemonkey-script/

// get referring board url
if (document.referrer==null) return;

// cleanup ref
var ref = document.referrer;

// To allow usage on forum category pages
// Ex. https://forum.unity.com/categories/ecs-for-unity.823/
if (ref.includes("categories")) {
    ref = ref.replace("https://forum.unity.com/categories/", "");
} else if (ref.includes("forums")) {
    ref = ref.replace("https://forum.unity.com/forums/", "");
}

// find board name from url
var dotPos = ref.indexOf('.');
if (dotPos==-1) return;
ref = ref.substring(0, dotPos).replaceAll("-", " ");

// get selection box that contains forum boards
var sel = document.getElementById("ctrl_nodes");

// loop to find match in the select items and url board name
for (var i = 0;i<sel.options.length;i++)
{
  var item = sel.options[i].text.trim();
  if (item.toLowerCase() == ref.toLowerCase())
  {
    sel.selectedIndex = i;
    break;
  }
}