Making the "Preposition Game" a little better (still not there)

word_game.js

function wordGame(words) {
    let clicks = 0;
    let correct = 0;

    function updateScore() {
        let score = document.querySelectorAll('.word-game-score-panel')[0];
        if (clicks == 0) {
            score.innerHTML = "The Preposition Game<br>Accuracy: 0%";
        } else {
            let accuracy = Math.round(correct / clicks * 100);
            score.innerHTML = `The Preposition Game<br>Accuracy: ${accuracy}%`;
        }
    }

    function createScoreArea() {
        let score = document.createElement("div");
        score.classList.add("word-game-score-panel");
        score.style.position = "fixed";
        score.style.top = "2%";
        score.style.right = "2%";
        score.style.backgroundColor = "white";
        score.style.border = "3px solid red";
        score.style.padding = "0.5em";
        score.innerHTML = "The Preposition Game<br>Accuracy: 0%";

        let body = document.getElementsByTagName("body");
        body[0].appendChild(score);
    }

    function printSolution(event) {
        clicks += 1;
        let element = event.currentTarget;
        let answer = element.getAttribute("data-answer");
        let selectedOptions = Array.from(element.selectedOptions).map(e => e.text);
        if (selectedOptions.includes(answer)) {
            correct += 1;
            element.style.border = "2px solid green";
        } else {
            element.style.border = "2px solid red";
        }
        updateScore();
    }
    
    function toRegexp(wordArray) {
        let expr = wordArray.join("|");
        return new RegExp(`\\b(${expr})\\b`, 'g');
    }

    function toOptions(wordArray) {
        let words = [""].concat(wordArray);
        return words.map(w => `<option>${w}</option>`)
                    .join("");    
    }

    function initGame() {
        theWordGameIsRunning = true;

        createScoreArea();

        let regexp = toRegexp(words);
        let prepOptions = toOptions(words);
        let prepSelect = `<select class="word-game" data-answer="$1" style="border: 2px solid black">${prepOptions}</select>`;

        let paragraphs = document.getElementsByTagName("p");
        for (let p of paragraphs) {
            p.innerHTML = p.innerHTML
                           .replace(regexp, prepSelect);

            let selections = p.querySelectorAll('.word-game');
            for (let e of selections) {
                e.addEventListener('change', printSolution);
            }
        }
    }

    function resetGame() {
        for (e of document.querySelectorAll('.word-game')) {
            e.selectedIndex = 0;
            e.style.border = "2px solid black";
        }
        clicks = 0;
        correct = 0;
        updateScore();
    }

    let selections = document.querySelectorAll('.word-game');
    if (selections.length > 0) {
        resetGame();
    } else {
        initGame();
    }
}
wordGame(["on", "at", "in"]);
wordGame(["for", "to", "by"]);