const seasonTextbox = document.getElementById('season-textbox');
const submitButton = document.getElementById('submit-button');

async function checkDataValidity() {
    let dataIsValid = true;
    
    if(seasonTextbox.value == "") dataIsValid = false;

    submitButton.disabled = !dataIsValid;
}
checkDataValidity();

seasonTextbox.addEventListener('keyup', checkDataValidity);
seasonTextbox.addEventListener('change', checkDataValidity);