tasks.js

document.addEventListener('DOMContentLoaded', function() {


    // By default, submit button is disabled
    document.querySelector('#submit').disabled = true;

    document.querySelector('#task').onkeyup = () => {
        if (document.querySelector('#task').value.length > 0) {
            document.querySelector('#submit').disabled = false;
        }else {
            document.querySelector('#submit').disabled = true;
        };
    };


    document.querySelector('form').onsubmit = () => {
        const task = document.querySelector('#task').value;

        const li = document.createElement('li');
        li.innerHTML = task;

        document.querySelector('#tasks').append(li);

        document.querySelector('#task').value = '';
        document.querySelector('#submit').disabled = true;


        return false
    };
});