monster-versions.js

function initmonsterversions() {    

let u = new URL(location.href).pathname.split('/');
u.pop();
const current =u.pop();
let result = u.join('/')+"/";

function compareVer(a, b) {
    function prep(t) {
        return ("" + t)
          .replace(/[^0-9\.]+/g, function(c){return "." + ((c = c.replace(/[\W_]+/, "")) ? c.toLowerCase().charCodeAt(0) - 65536 : "") + "."})
          .replace(/(?:\.0+)*(\.-[0-9]+)(\.[0-9]+)?\.*$/g, "$1$2")
          .split('.');
    }
    a = prep(a);
    b = prep(b);
    for (var i = 0; i < Math.max(a.length, b.length); i++)  {
        a[i] = ~~a[i];
        b[i] = ~~b[i];
        if (a[i] > b[i])
            return 1;
        else if (a[i] < b[i])
            return -1;
    }
    return 0;
}


const lastVersionContainer = document.createElement('div');
lastVersionContainer.setAttribute('style','margin-bottom:10px;');
const constainer = document.createElement('div');
constainer.setAttribute('style','display: flex;align-items: center;justify-content: flex-start;gap: 10px;align-content: center;');
constainer.appendChild(document.createTextNode('versions'));
const selectElement = document.createElement('select');
selectElement.setAttribute('onChange','location="'+result+'"+this.value');
selectElement.setAttribute('id','monster-versions');
    selectElement.add(new Option('1.26.1'));
selectElement.add(new Option('1.26.0'));
selectElement.add(new Option('1.25.0'));
selectElement.add(new Option('1.24.0'));
selectElement.add(new Option('1.23.0'));
selectElement.add(new Option('1.22.0'));
selectElement.add(new Option('1.21.1'));
selectElement.add(new Option('1.21.0'));
selectElement.add(new Option('1.20.2'));
selectElement.add(new Option('1.20.1'));
selectElement.add(new Option('1.20.0'));
selectElement.add(new Option('1.19.0'));
selectElement.add(new Option('1.18.0'));
selectElement.add(new Option('1.17.2'));
selectElement.add(new Option('1.17.1'));
selectElement.add(new Option('1.17.0'));
selectElement.add(new Option('1.16.1'));
selectElement.add(new Option('1.16.0'));
selectElement.add(new Option('1.15.5'));
selectElement.add(new Option('1.15.4'));
selectElement.add(new Option('1.15.3'));
selectElement.add(new Option('1.15.2'));
selectElement.add(new Option('1.15.0'));

selectElement.value=current;
constainer.append(selectElement);
document.getElementById('sidebar-main-content').prepend(constainer);
document.getElementById('sidebar-main-content').prepend(lastVersionContainer);

    if(compareVer(current,'1.26.1')===-1) {;
        let infocontainer = document.createElement('div');
        let infolink = document.createElement('a');
        let lasturl = new URL(location.href)