DresdenBacklight

// ==UserScript==
// @name DresdenBacklight
// @namespace Violentmonkey Scripts
// @grant none
// ==/UserScript==

const whiteColor = '#ffffff'

function findPlace() {

    let currentPlace = document.getElementsByName('freeTimeContainer:free_time.place')[0];

    if (typeof(currentPlace) !== 'undefined') {

        currentPlace = currentPlace.selectedIndex;

        for (let obj in arrayForPlaces) {
            if (currentPlace === arrayForPlaces[obj].idPlace) {
                backlighting(arrayForPlaces[obj].timeTOPlay, arrayForPlaces[obj].color);
            }
        }
    }
}

function backlighting(userWord, color) {

    let word = userWord;
    let queue = [document.body];
    let curr;
    while (curr = queue.pop()) {
        if (!curr.textContent.match(word)) continue;
        for (let i = 0; i < curr.childNodes.length; ++i) {
            switch (curr.childNodes[i].nodeType) {
                case Node.TEXT_NODE : // 3
                    if (curr.childNodes[i].textContent.match(word)) {
                        console.log("Found!");
                        console.log(curr);
                        curr.style.background = color;
                    }
                    break;
                case Node.ELEMENT_NODE : // 1
                    queue.push(curr.childNodes[i]);
                    break;
            }
        }
    }
}

let arrayForPlaces = [{
    idPlace: 14,
    timeTOPlay: '19:30 - 20:00',
    color: whiteColor
},
    {
        idPlace: 15,
        timeTOPlay: '20:30 - 21:00',
        color: whiteColor
    },
    {
        idPlace: 16,
        timeTOPlay: '21:30 - 22:00',
        color: whiteColor
    }, {
        idPlace: 28,
        timeTOPlay: '18:30 - 19:00',
        color: whiteColor
    }];

findPlace();