it did not work for me, why?

const usernameInput = document.getElementById("username"); const passwordInput = document.getElementById("password"); const telephoneInput = document.getElementById("telephone"); const emailInput = document.getElementById("email");

/**

• VALIDATORS
• */

// Can only contain letters a-z in lowercase function isValidUsername(username) { return/^[a-z]+$/.test(username); }

// Must contain a lowercase, uppercase letter and a number function isValidPassword(password) { return/[a-z]/.test(password) && /[A-Z]/.test(password) && /[0-9]/.test(password) && /^(?=.\d)(?=.[a-z])(?=.[A-Z]).$/.test(password); }

// The telephone number must be in the format of (555) 555-5555 function isValidTelephone(telephone) { return /^(\d{3})\s{3}-\d{4}$/.test(telephone); }

// Must be a valid email address function isValidEmail(email) {}

/**

• FORMATTING FUNCTIONS
• */

function formatTelephone(text) {}

/**

• SET UP EVENTS
• */

function showOrHideTip(show, element) { // show element when show is true, hide when false if (show) { element.style.display = "inherit"; } else { element.style.display = "none"; } }

function createListener(validator) { return e => { const text = e.target.value; const valid = validator(text); const showTip = text !== "" && !valid; const tooltip = e.target.nextElementSibling; showOrHideTip(showTip, tooltip); }; }

usernameInput.addEventListener("input", createListener(isValidUsername));

passwordInput.addEventListener("input", createListener(isValidPassword));

telephoneInput.addEventListener("input", createListener(isValidTelephone));

emailInput.addEventListener("input", createListener(isValidEmail));