Alert if email is valid or invalid

Hello. I am trying to have someone enter an email address and if it’s invalid, it prompts that it’s an invalid email address. I have my code here and it keeps saying “Uncaught TypeError: Cannot read properties of undefined (reading ‘match’) at ValidateEmail”

'use strict'
///listen to 29:35 in voice notes!!! ///

/* Add a function to get the current date and time.
Write the date on the page in a user friendly format */

// Create function to capitalize first char of firstName variable //
const capFirstChar = (str) => str.charAt(0).toUpperCase() + str.slice(1);

// Get user's name //
const firstName = prompt('What is your name?');

// Switch statement to get time of day //
const currTime = new Date();
const currHour = currTime.getHours();
switch (true) {
    case (currHour < 12):
        document.getElementById('greeting').innerHTML = `Good morning, ${capFirstChar(firstName)}!`;
        console.log("Good morning!");
    case (currHour > 12 && currHour < 17):
        document.getElementById('greeting').innerHTML = `Good afternoon, ${capFirstChar(firstName)}!`;
        console.log("Good afternoon!");
        document.getElementById('greeting').innerHTML = `Good evening, ${capFirstChar(firstName)}!`;
        console.log("Good evening!");

const userEmail = '';
const emailSplit = userEmail.split('@');
const var1 = userEmail.split([0]);
const var2 = userEmail.split([1]);

//Function to validate email //

// function validEmail(email) {
//     const emailRegex = /[-\w.]+@([A-z0-9][-A-z0-9]+\.)+[A-z]{2,4}/;
//     const valid = email.match(emailRegex);
//     return valid;
// };

function ValidateEmail(input) {

    var validRegex = /^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/;

    if (input.value.match(validRegex)) {

        alert("Valid email address!");


        return true;

    } else {

        alert("Invalid email address!");


        return false;


let testEmail = prompt('What is your email?');
<!DOCTYPE html>
<html lang="en">

    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <link rel="stylesheet" href="trivia.css">
    <title>Trivia Game!</title>

        <p id="greeting"></p>
        <h1>Trivia Game!</h1>
        <!-- <p class="between">(Between 1 and 20)</p> -->
        <button class="btn again">Again!</button>
        <div class="number">?</div>
        <section class="left">
            <input type="number" class="guess" />
            <button class="btn check">Check!</button>
        <section class="right">
            <p class="message">Start guessing...</p>
            <p class="label-score">💯 Score: <span id="score">0</span></p>
            <p class="label-highscore">
                🥇 Highscore: <span id="highscore">0</span>
    <script src="trivia.js"></script>



The first error I am getting with your code is:

“Uncaught TypeError: input.value is undefined”

This is referring to the following line in the ValidateEmail function:

 if (input.value.match(validRegex)) {

Are you sure that input.value is what you want here? I would add a console.log(input) at the beginning of that function to verify the value of input.

Hello there. Input is the parameter of the function. So whenever I call the function, I put in the variable of what the user was prompted, which was asking them to enter an email

When you call ValidateEmail(testEmail), what data type is testEmail?

Once you figure that out, then ask yourself how do you normally reference that data type?

Also, you have the following two times in your code:


What do you think document.form1 is?

This doesn’t create a form, it creates a prompt, but you are trying to access the value the user is entering into the prompt as if it was a form.

I tried changing it up a bit and found another code online here JavaScript : email validation - w3resource and tried to make it work, but I guess it won’t work? lol. I originally had this, but it failed miserably — kept looping. ):

//Function to validate email //

function validEmail(email) {
    const emailRegex = /[-\w.]+@([A-z0-9][-A-z0-9]+\.)+[A-z]{2,4}/;
    const valid = email.match(emailRegex);
    return valid;

const emailAddress = prompt('Please enter your email');
while (!validEmail(emailAddress)) {
    prompt('Please enter a valid email');
    // console.log('Please enter a valid email');

Figured it out!!!

<!DOCTYPE html>
<html lang="en">

    <meta charset="utf-8">
    <title>JavaScript form validation - checking email</title>
    <link rel='stylesheet' href='form-style.css' type='text/css' />

<body onload='document.form1.text1.focus()'>
    <div class="mail">
        <h2>Input an email and Submit</h2>
        <form name="form1" action="#">
                <li><input type='text' name='text1' /></li>
                <li class="submit"><input type="submit" name="submit" value="Submit"
                        onclick="ValidateEmail(document.form1.text1)" /></li>
    <script src="email-validation.js"></script>

function ValidateEmail(inputText) {
    var mailformat = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
    if (inputText.value.match(mailformat)) {
        return true;
    else {
        alert("You have entered an invalid email address!");
        return false;