const userAnswer = operatorInput.value.trim
();
const correctAnswer = operatorInput.dataset
.correct;
if (userAnswer !== correctAnswer) {
operatorInput.style.borderColor = 'red';
operatorInput.style.borderColor = 'green'
;
const messageDiv = document.getElementById
('message');
messageDiv.textContent = '所有题目都正确!';
messageDiv.className = 'message correct';
messageDiv.textContent =
'有错误的题目,请检查后重新提交。';
messageDiv.className = 'message wrong';
window.onload = function () {