Tampermonkey userscript for Kimai to list the each months expected payment

paycount.user.js

// ==UserScript==
// @name         PayCount
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  List each months expected payment
// @author       You
// @match        https://yourdomain.com/timesheet/
// @icon         https://www.google.com/s2/favicons?sz=64&domain=yourdomain.com
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    function finishUp(count, sumRect) {
        let rect = table.tHead.children[0].children[6].getBoundingClientRect();
        let div = document.createElement("div");
        div.style.borderStyle = "solid";
        div.style.borderColor = "#f00";
        div.style.borderWidth = "2px";
        div.style.position = "absolute";
        div.style.top = sumRect.top + "px";
        div.style.left = sumRect.left + "px";
        div.style.height = sumRect.bottom - sumRect.top + "px";
        div.style.width = sumRect.right - sumRect.left + "px";
        document.body.appendChild(div);
        let label = document.createElement("label");
        label.innerHTML += count + " €";
        label.style.display = "block";
        label.style.textAlign = "right";
        label.style.position = "absolute";
        label.style.top = sumRect.bottom - 4 + "px";
        label.style.left = sumRect.left + "px";
        label.style.width = sumRect.right - sumRect.left + "px";
        document.body.appendChild(label);
    }

    let currentMonth = new Date().getMonth() + 1;
    let table = document.querySelector("table.table.table-hover.dataTable");
    let rows = table.tBodies[0].children;
    let count = 0.0;
    let sumRect = {'top': Infinity, 'bottom': 0, 'left': Infinity, 'right': 0};
    for (let row of rows) {
        let rowMonth = parseInt(row.children[1].innerText.replace(/(\d{2})\.(\d{2})\.(\d{4})/, '$2'), 10);
        if (rowMonth != currentMonth) {
            row.style.borderTop = "10px solid transparent";
            finishUp(count, sumRect);
            count = 0.0;
            sumRect = {'top': Infinity, 'bottom': 0, 'left': Infinity, 'right': 0};
            currentMonth = rowMonth;
        }
        let rowCount = parseFloat(row.children[6].innerText.replace(',', '.').replace('€', '').trim());
        if (!isNaN(rowCount)) {
            count += rowCount;
        }
        let rowCountRect = row.children[6].getBoundingClientRect();
        sumRect.top = Math.min(sumRect.top, rowCountRect.top + 10);
        sumRect.left = Math.min(sumRect.left, rowCountRect.left);
        sumRect.bottom = Math.max(sumRect.bottom, rowCountRect.bottom - 10);
        sumRect.right = Math.max(sumRect.right, rowCountRect.right);
    }
    finishUp(count, sumRect);
    // Your code here...
})();

After installing this you still need to adjust the domain/url to whatever your kimai instance has.