zetamac.js

// url: https://arithmetic.zetamac.com/
// example: solve(1);

const solve = (delay) => {
  setInterval(() => {
    const startDiv = document.getElementsByClassName("start")[0];
    const leftDiv = document.getElementsByClassName("left")[0];
    const problemSpan = document.getElementsByClassName("problem")[0];
    const answerInput = document.getElementsByClassName("answer")[0];

    const doesStartDivExists = startDiv != undefined && startDiv.style.display != "none";
    const doesLeftDivExists = leftDiv != undefined;
    const doesProblemDivExists = problemSpan != undefined;
    const doesAnswerDivExists = answerInput != undefined;

    if (!doesStartDivExists || !doesLeftDivExists || !doesProblemDivExists || !doesAnswerDivExists)
      return;

    const secondsLeft = parseInt(leftDiv.textContent.split(": ")[1]);
    if (secondsLeft <= 0)
      return;

    const sanitizedProblem = problemSpan.textContent.replace("÷", "/").replace("×", "*").replace("–", "-");
    const generatedAnswer = eval(sanitizedProblem);

    answerInput.value = generatedAnswer;
    answerInput.dispatchEvent(new Event('input', { bubbles: true }));
  }, delay);
}