t4c-autologin.user.js

// ==UserScript==
// @name         T4C Automatic Login
// @namespace    http://tampermonkey.net/
// @version      0.1
// @author Henrik Karlsson
// @author       You
// @match        http://192.168.0.55/*
// @grant        none
// ==/UserScript==
'use strict'

;(function() {
    const createAutomaticLoginCheckbox = () => {
        const loginTBody = document.querySelector('#fields > table > tbody')
        const validationResultTr = document.querySelector('#fields > table > tbody > tr:nth-child(5)')
        const loginButton = document.querySelector('#btnLogin_5')

        const tr = document.createElement('tr')

        const spacerTd = document.createElement('td')
        spacerTd.innerHTML = ' '
        tr.appendChild(spacerTd)

        const td = document.createElement('td')

        const input = document.createElement('input')
        input.type = 'checkbox'
        input.id = 'automatic_login'
        input.checked = localStorage.getItem('automatic_login') === 'true'
        td.appendChild(input)

        const label = document.createElement('label')
        label.innerText = 'Logga in automatiskt'
        label.htmlFor = 'automatic_login'
        td.appendChild(label)

        tr.appendChild(td)

        loginTBody.insertBefore(tr, validationResultTr)

        loginButton.addEventListener('click', () => {
            localStorage.setItem('automatic_login', input.checked ? 'true' : 'false')
        })
    }

    const hasVisibleErrorDialog = () => document.querySelector('.popup')

    const tryAutomaticLogin = () => {
        if (localStorage.getItem('automatic_login') === 'true') {
            const loginButton = document.querySelector('#btnLogin_5')
            loginButton.click()
        }
    }

    const tryAugmentLogoutLink = () => {
        const logoutLink = document.querySelector('#NavMenu1_lblLogout_11')
        if (!logoutLink) {
            return
        }

        logoutLink.addEventListener('click', () => {
            localStorage.removeItem('automatic_login')
        })
    }

    if (window.location.pathname === '/T4C/Content/Login.aspx') {
        createAutomaticLoginCheckbox()

        if (!hasVisibleErrorDialog()) {
            tryAutomaticLogin()
        }
    }

    tryAugmentLogoutLink()
})()