document.getElementById('check').onclick = function(){ let login = document.getElementById('login').value; let password = document.getElementById('password').value; let successBox = document.getElementById('successBox'); successBox.style.display='none' let failureBox = document.getElementById('failureBox'); failureBox.style.display='none' if (login == 'admin' && password == 'qwerty') successBox.style.display='block' else failureBox.style.display='block' }