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How can I get an animation to run when input submit is clicked in javascript?

I have a form which I want each time I validate if the information is empty, to run an animation of a library that imports from CSS called Animate.CSS, so I have created a function to validate each input, so if one is empty, it runs an "shake" animation of the library I mentioned. At the same time, the class has to be added, but removed at the end in case the user does not write in the input again, the animation runs.
This is my form:
<form action="" id="form">
<label for="name">Name</label>
<input
type="text"
placeholder="Name"
id="name"
minlength="3"
required
/>
<br />
<label for="email">Email</label>
<input type="email" placeholder="Emai" id="email" required />
<br />
<label for="subject">Subject</label>
<input
type="text"
placeholder="Subject"
id="subject"
minlength="3"
required
/>
<br />
<label for="message">Message</label>
<textarea
name="message"
id="message"
minlength="5"
placeholder="Message"
required
style="resize: none; height: 200px"
></textarea>
<br />
<button type="submit" class="paper-btn" id="submit">
Send message
</button>
</form>
And Javascript:
(function () {
var form = document.getElementById("form"),
name = form.name,
email = form.email,
subject = form.subject;
message = form.message;
function validateName(e) {
if (name.value == "" || name.value == null) {
form.classList.add("animate__animated");
name.classList.add("animate__shakeX");
e.preventDefaul();
} else {
console.log("error");
}
}
function validateEmail(e) {
if (email.value == "" || email.value == null) {
email.classList.add("animate__animated");
email.classList.add("animate__shakeX");
e.preventDefaul();
}
}
function validateSubject(e) {
if (subject.value == "" || subject.value == null) {
subject.classList.add("animate__animated");
subject.classList.add("animate__shakeX");
e.preventDefaul();
}
}
function validateMessage(e) {
if (subject.value == "" || subject.value == null) {
message.classList.add("animate__animated");
message.classList.add("animate__shakeX");
e.preventDefaul();
}
}
function validateForm(e) {
validateName(e);
validateEmail(e);
validateSubject(e);
validateMessage(e);
}
form.addEventListener("submit", validateForm);
});
This code works, apparently, but it happens when I click on refresh and not when I click on submit:
var form = document.getElementById("name");
if (form.value == "" || form.value == null) {
form.classList.add("animate__animated");
form.classList.add("animate__shakeX");
}

There was a lot going on in there so I simplified some stuff to make a little more sense to me but you should go through your code and check for errors as there are quite a few there. I have made a little demo of what I assume you wanted the form to do.
document.getElementById("form").addEventListener("submit", (e) => {
validateName();
validateEmail();
validateSubject();
validateMessage();
e.preventDefault();
setTimeout(removeAnimations, "2000");
})
function validateName() {
const name = document.getElementById("name");
if(name.value.length < 3) {
name.classList.add("animate__red", "animate__animated");
} else {
name.classList.remove("animate__red");
}
}
function validateEmail() {
const ele = document.getElementById("email");
if(ele.value.length < 1) {
ele.classList.add("animate__red", "animate__animated");
} else {
ele.classList.remove("animate__red", "animate__animated");
}
}
function validateSubject() {
const ele = document.getElementById("subject");
if(ele.value.length < 3) {
ele.classList.add("animate__red", "animate__animated");
} else {
ele.classList.remove("animate__red", "animate__animated");
}
}
function validateMessage() {
const ele = document.getElementById("message");
if(ele.value.length < 3) {
ele.classList.add("animate__red", "animate__animated");
} else {
ele.classList.remove("animate__red", "animate__animated");
}
}
function removeAnimations() {
document.querySelectorAll(".animate__red")
.forEach((ele) => {
ele.classList.remove("animate__red", "animate__animated");
});
}
.animate__red {
background-color: red;
}
<form action="" id="form">
<label for="name">Name</label>
<input type="text" placeholder="Name" id="name" minlength="3" />
<br />
<label for="email">Email</label>
<input type="email" placeholder="Email" id="email" />
<br />
<label for="subject">Subject</label>
<input type="text" placeholder="Subject" id="subject" minlength="3" />
<br />
<label for="message">Message</label>
<textarea name="message" id="message" minlength="5" placeholder="Message" style="resize: none; height: 200px"></textarea>
<br />
<button type="submit" class="paper-btn" id="submit">
Send message
</button>
</form>

preventDefault() cause problem on validating the form

the code below was written to validate simple html form with JavaScript and preventDefault() method means that if the required fields are empty then stop form submission and display error or otherwise submit the form if the required fields are not empty.
The problem comes when I click the submit button the form isn't working.
Can anyone please help me to solve the problem?
let form = document.getElementById("signUp");
let uname = document.forms["myForm"]["userName"].value;
let uemail = document.forms["myForm"]["userEmail"].value;
function validateForm() {
if (uname == " ") {
alert("Name is Empty");
} else if (uemail == " ") {
alert("Email is Empty");
return false;
}
return true;
}
form.addEventListener("submit", function(e) {
e.preventDefault();
validateForm();
});
<form id="signUp" name="myForm">
Name: <input type="text" name="uname" id="userName">
<br> Email: <input type="email" name="email" id="userEmail">
<button type="submit">sign up</button>
</form>

With e.preventDefault() you say that the form should not be submitted.
So you only want to call if in case the validation returns false.
Besides that, your uname and uemail is set before the form is submitted. So it won't contain the state of the input fields at the time the form is submitted. You have to move them into your validateForm function.
let form = document.getElementById("signUp");
function validateForm() {
let uname = document.forms["myForm"]["userName"].value;
let uemail = document.forms["myForm"]["userEmail"].value;
if (uname == " ") {
alert("Name is Empty");
} else if (uemail == " ") {
alert("Email is Empty");
return false;
}
return true;
}
form.addEventListener("submit", function(e) {
if (!validateForm()) {
e.preventDefault();
}
});
<form id="signUp" name="myForm">
Name: <input type="text" name="uname" id="userName">
<br> Email: <input type="email" name="email" id="userEmail">
<button type="submit">sign up</button>
</form>
And uname == " " does not test if the name is empty. It tests if it consists of one character that is a space. The same is for uemail == " ". You probably looking for uname.trim() == ""
As you need to verify the data on the server anyways. And in some way need to display an error if the validation fails on the server side.
It is often sufficient to rely on the HTML solutions to verify the form data (if the browser support is decent enough even if it is not complete).
Something like this:
.error {
display: none;
}
input:not(:placeholder-shown):invalid +.error {
display: block;
}
<form id="signUp" name="myForm">
Name: <input type="text" name="uname" id="userName" placeholder="Name" pattern="^(?!^ +$)([\w -&]+)$" required>
<div class="error">Name must not be empty</div>
<br> Email: <input type="email" name="email" id="userEmail" placeholder="Email" required>
<div class="error">Email must be valid</div>
<button type="submit">sign up</button>
</form>

const form = document.getElementById("signUp");
form.addEventListener("submit", (e) => {
e.preventDefault();
if(validate()) {
form.submit()
}
});
const validate = () => {
const name = document.querySelector("#userName");
const email = document.querySelector("#email");
let hasError = false;
if(!(name.value && name.value.length > 4)) {
const nameErr = document.querySelector("#user-name-error");
nameErr.textContent = "Name is required";
hasError = true;
}
if(!(name.value && name.value.length > 0)) {
const emailErr = document.querySelector("#user-email-error");
emailErr.textContent = "Email is required";
hasError = true;
}
return !hasError;
};
<form id="signUp" name="myForm">
<div class="form-group">
<label for="userName">Name: </label>
<input type="text" name="uname" id="userName" />
<p id="user-name-error" style="color: red;"></p>
</div>
<div class="form-group">
<label for="userEmail">Email: </label>
<input type="email" name="email" id="email" />
<p id="user-email-error" style="color: red;"></p>
</div>
<button type="submit">sign up</button>
</form>

<form id="signUp" name="myForm">
<div class="form-group">
<label for="userName">Name: </label>
<input type="text" name="uname" id="userName" required minlength="4"/>
</div>
<div class="form-group">
<label for="userEmail">Email: </label>
<input type="email" name="email" id="email" required pattern="[^#]*#[^.]*\..*"/>
</div>
<button type="submit">sign up</button>
</form>
This is an example using only html, it is only for your use case of course if you want to add more complexe validation use javascript

Why the output from javascript just shown for a short period of time?

I am developing a Registration form for my assignment. All things are working but when I click on the submit button, the warning messages on the label are just shown for a very short period of time. I am using eclipse and apache tomacat. here is my code.
JSP Code:
<form method="post">
<h2>Welcome to AP Auctions. Please Enter Bid</h2>
<span id="msg" style="color:red;font-size:25px"></span><br/>
<label id="itemid_l">Item Id:</label> <input type="text" name="itemid" id="itemid"/><br/>
<label id="itemname_l">Item Name:</label> <input type="text" name="itemname" id="itemname"/><br/>
<label id="uname_l">Your Name:</label> <input type="text" name="uname" id="uname"/><br/>
<label id="email_l">Your Email Address:</label> <input type="text" name="email" id="email"/><br/>
<label id="amount_l">Amount Bid:</label> <input type="number" name="amount" id="amount"/><br/>
<label id="autoincrement_l">Auto-increment to match other bidders:</label><input type="checkbox" name="autoincrement" id="autoincrement"><br/>
<input type="submit" value="Submit Bid" onclick="validate()"/>
</form>
Javascript Code:
function validate()
{
var itemid=document.getElementById("itemid").value;
var itemname=document.getElementById("itemname").value;
var uname=document.getElementById("uname").value;
var email=document.getElementById("email").value;
var amount=document.getElementById("amount").value;
var autoincrement=document.getElementById("autoincrement");
var flag=true;
if(itemid.length==0){
flag=false;
document.getElementById("itemid_l").innerHTML="<b>Required field!</b> Item Id: ";
}
if(itemname.length==0){
flag=false;
document.getElementById("itemname_l").innerHTML="<b>Required field!</b> Item Name: ";
}
if(uname.length==0){
flag=false;
document.getElementById("uname_l").innerHTML="<b>Required field!</b> Your Name: ";
}
if(email.length==0){
flag=false;
document.getElementById("email_l").innerHTML="<b>Required field!</b> Your Email Address: ";
}
if(amount.length==0){
flag=false;
document.getElementById("amount_l").innerHTML="<b>Required field!</b> Amount Bid: ";
}
if(!autoincrement.checked){
flag=false;
document.getElementById("autoincrement_l").innerHTML="<b>Required field!</b> Auto-increment to match other bidders:: ";
}
if(flag==true){
alert('Good job!!');
return true;
}
else
{
document.getElementById("msg").innerHTML="Required data is missing. Please fill";
return false;
}
}
Any suggestion will help me a lot..

You can use onsubmit event so that whenever user click on submit button this gets call and if the function validate() return true form will get submitted else it will not submit form .
Demo code :
function validate() {
var itemid = document.getElementById("itemid").value;
var itemname = document.getElementById("itemname").value;
var uname = document.getElementById("uname").value;
var email = document.getElementById("email").value;
var amount = document.getElementById("amount").value;
var autoincrement = document.getElementById("autoincrement");
var flag = true;
if (itemid.length == 0) {
flag = false;
document.getElementById("itemid_l").innerHTML = "<b>Required field!</b> ";
} else {
//if fill remove error any
document.getElementById("itemid_l").innerHTML = ""
}
if (itemname.length == 0) {
flag = false;
document.getElementById("itemname_l").innerHTML = "<b>Required field!</b> ";
} else {
//if fill remove error any
document.getElementById("itemname_l").innerHTML = "";
}
if (uname.length == 0) {
flag = false;
document.getElementById("uname_l").innerHTML = "<b>Required field!</b> ";
} else {
document.getElementById("uname_l").innerHTML = "";
}
if (email.length == 0) {
flag = false;
document.getElementById("email_l").innerHTML = "<b>Required field!</b> ";
} else {
document.getElementById("email_l").innerHTML = "";
}
if (amount.length == 0) {
flag = false;
document.getElementById("amount_l").innerHTML = "<b>Required field!</b>";
} else {
document.getElementById("amount_l").innerHTML = "";
}
if (!autoincrement.checked) {
flag = false;
document.getElementById("autoincrement_l").innerHTML = "<b>Required field!</b>";
} else {
document.getElementById("autoincrement_l").innerHTML = "";
}
if (flag == true) {
document.getElementById("msg").innerHTML = "";
alert('Good job!!');
flag = true; //do true
} else {
document.getElementById("msg").innerHTML = "Required data is missing. Please fill";
flag = false; //do false
}
return flag; //return flag
}
<!--add onsubmit -->
<form method="post" id="forms" onsubmit="return validate()">
<h2>Welcome to AP Auctions. Please Enter Bid</h2>
<span id="msg" style="color:red;font-size:25px"></span><br/>
<!--give id to span instead of label-->
<label> <span id="itemid_l"></span>Item Id:</label> <input type="text" name="itemid" id="itemid" /><br/>
<label><span id="itemname_l"></span>Item Name:</label> <input type="text" name="itemname" id="itemname" /><br/>
<label><span id="uname_l"></span>Your Name:</label> <input type="text" name="uname" id="uname" /><br/>
<label><span id="email_l"></span>Your Email Address:</label> <input type="text" name="email" id="email" /><br/>
<label><span id="amount_l"></span>Amount Bid:</label> <input type="number" name="amount" id="amount" /><br/>
<label><span id="autoincrement_l"></span>Auto-increment to match other bidders:</label><input type="checkbox" name="autoincrement" id="autoincrement"><br/>
<input type="submit" value="Submit Bid" />
</form>
Also , if you just need to check for empty field you can just use required attribute on input tag like below :
<form method="post">
<h2>Welcome to AP Auctions. Please Enter Bid</h2>
<span id="msg" style="color:red;font-size:25px"></span><br/>
<!--added required attribute-->
<label id="itemid_l">Item Id:</label> <input type="text" name="itemid" id="itemid" required/><br/>
<label id="itemname_l">Item Name:</label> <input type="text" name="itemname" id="itemname" required/><br/>
<label id="uname_l">Your Name:</label> <input type="text" name="uname" id="uname" required/><br/>
<label id="email_l">Your Email Address:</label> <input type="text" name="email" id="email" required/><br/>
<label id="amount_l">Amount Bid:</label> <input type="number" name="amount" id="amount"required/><br/>
<label id="autoincrement_l">Auto-increment to match other bidders:</label><input type="checkbox" name="autoincrement" id="autoincrement" required><br/>
<input type="submit" value="Submit Bid"/>
</form>

The onsubmit event handler javascript not working

I have a problem. When I clicked the submit button nothing happens, even when I filled out the username and password with numbers (I don't want the username and password contains any number so I did make the condition for it), there is no alert display. I do not know where the problem comes from? Can you guys help me with this
Note: the reset function works fine
function validateInput() {
var firstName = document.forms["sign_up"]["firstName"];
var lastName = document.forms["sign_up"]["lastName"];
var email = document.forms["sign_up"]["email"];
var reg = /^[a-zA-Z]+$/;
if (firstName.value !== '' || lastName.value !== '' || email.value !== '') {
if (firstName.value.match(reg) && lastName.value.match(reg)) {
alert("Form is submitted");
// return true;
return false; // for the demo, so it doesn't submit
} else {
if (firstName.value.match(reg) === false) {
document.getElementById("error").innerHTML = "Numbers are not allowed in username";
return false;
} else if (lastName.value.match(reg) === false) {
document.getElementById("error").innerHTML = "Numbers are not allowed in password";
return false;
}
}
}
}
function reset() {
document.getElementById("first").innerHTML = "";
document.getElementById("last").innerHTML = "";
document.getElementById("email").innerHTML = "";
}
<form id="sign_up" onsubmit="return validateInput()">
<p id="error"></p>
<label for="firstName">First Name</label>
<input type="text" id="firstName" value="" placeholder="Enter your first name">
<label for="lastName">Last Name</label>
<input type="text" id="lastName" value="" placeholder="Enter your last name">
<label for="email">Email</label>
<input type="email" id="email" value="" placeholder="Enter your email">
<button type="submit">Submit</button>
<button type="button" onclick="reset();">Cancel</button>
</form>

Use the Pattern attribute in input for validation like below
<input type="text" id="firstName" value="" pattern="[^0-9]*" title="Numbers are not allowed" placeholder="Enter your first name">
for more references: https://www.w3schools.com/tags/att_input_pattern.asp
And for reset functionality use reset
<input type="reset" value="reset">
It's better than create a special function for it and it saves your number of lines:-)

First, try to avoid to inline event handlers as they are not rec-emended at all. Also to reset form values you can simply use reset() method on the form.
Also, do not use innerHTML just to set the text of your error. You can use textContent instead which is better fit in your example.
You can use addEventListener with submit event to check for validation on your firstname and lastname.
I have fixed your code and its all working as expected.
Live Working Demo:
let form = document.getElementById("sign_up")
var firstName = document.getElementById("firstName")
var lastName = document.getElementById("lastName")
var email = document.getElementById("email")
var reset = document.getElementById("clearValues")
var reg = /^[a-zA-Z]+$/;
form.addEventListener('submit', function(e) {
e.preventDefault()
if (firstName.value != '' || lastName.value != '' || email.value != '') {
if (firstName.value.match(reg) && lastName.value.match(reg)) {
alert("Form is submitted");
} else if (!firstName.value.match(reg)) {
document.getElementById("error").textContent = "Numbers are not allowed in username";
} else if (!lastName.value.match(reg)) {
document.getElementById("error").textContent = "Numbers are not allowed in password";
}
}
})
reset.addEventListener('click', function(e) {
document.getElementById("sign_up").reset();
})
input {
display:block;
}
<head>
</head>
<body>
<form id="sign_up" action="#">
<p id="error"></p>
<label for="firstName">First Name</label>
<input type="text" id="firstName" value="" placeholder="Enter your first name">
<label for="lastName">Last Name</label>
<input type="text" id="lastName" value="" placeholder="Enter your last name">
<label for="email">Email</label>
<input type="email" id="email" value="" placeholder="Enter your email">
<button type="submit">
Submit
</button>
<button type="button" id="clearValues" onclick="reset();">
Cancel
</button>
</form>
</body>

You don't need to return a function in onsubmit event. This should work fine.
<form id="sign_up" onsubmit="validateInput()">
Reference:
https://www.w3schools.com/jsref/event_onsubmit.asp

How to get this form validation script working

I have created a form and a form validation script that checks if all fields are filled in, the name and city fields contain only letters, the age and phone fields contain only numbers and if the entered email is a valid one. When used in the console, all of the statements work, but when I fill in every field, or fill in invalid values in the email field or phone number and age field, I still get an error message saying that the name and city field must contain only letters.
I have tried writing out every statement alone and also checking them one by one.
HTML & JS
<form>
<div class="form-group">
<label for="inputName">Name</label>
<input type="name" class="form-control" id="inputName" placeholder="Enter name">
</div>
<div class="form-group">
<label for="inputName">Age</label>
<input type="age" class="form-control" id="inputAge" placeholder="Enter age">
</div>
<div class="form-group">
<label for="inputCity">City</label>
<input type="city" class="form-control" id="inputCity" placeholder="Enter city">
</div>
<div class="form-group">
<label for="InputEmail1">Email address</label>
<input type="email" class="form-control" id="InputEmail1" aria-describedby="emailHelp" placeholder="Enter email">
<!-- <small id="emailHelp" class="form-text text-muted">We'll never share your email with anyone else.</small> -->
</div>
<div class="form-group">
<label for="inputPhone">Phone number</label>
<input type="phone" class="form-control" id="inputPhone" placeholder="Phone number">
</div>
<button type="button" class="btn btn-primary submit">Submit</button>
<button type="button" class="btn btn-primary erase">Erase</button>
</form>
<script>
function validateForm() {
var name_cityRegex = /^[a-zA-Z]+$/;
var emailRegex = /^(([^<>()\[\]\.,;:\s#\"]+(\.[^<>()\[\]\.,;:\s#\"]+)*)|(\".+\"))#(([^<>()[\]\.,;:\s#\"]+\.)+[^<>()[\]\.,;:\s#\"]{2,})$/i;
var age_phoneRegex = /^\d+$/;
var nameValue = $('#inputName').val();
var cityValue = $('#inputCity').val();
var ageValue = $('#inputAge').val();
var phoneValue = $('#inputPhone').val();
var nameResult = name_cityRegex.test(nameValue);
var cityResult = name_cityRegex.test(cityValue);
var ageResult = age_phoneRegex.test(ageValue);
var phoneResult = age_phoneRegex.test(phoneValue);
var mailValue = $('#InputEmail1').val();
var mailResult = emailRegex.test(mailValue);
$(".btn.btn-primary.submit").click(function () {
$('.form-control').each(function () {
if ($(this).val() == "") {
$('.alert.alert-danger').show();
}
else if (nameResult == false || cityResult == false) {
$('.alert.alert-danger').text("Please use letters only in the fields 'Name' and 'City'");
$('.alert.alert-danger').show();
return false;
}
else if (ageResult == false || phoneResult == false) {
$('.alert.alert-danger').text("Please use digits only in the fields 'Age' and 'Phone number'");
$('.alert.alert-danger').show();
return false;
}
else if (mailResult == false) {
$('.alert.alert-danger').text("Please enter a valid email adress");
$('.alert.alert-danger').show();
return false
}
return true;
})
});
</script>
When I leave all fields empty the warning is ok. But when I do anything else I only get the warning that I can only use letters in the fields Name and City.
All help is greatly appreciated for a beginner!

I think you are failing to reassign the variables outside of the onClick function. I have tested below code and it works for me, i admit it is probably not a perfect solution reassigning all the variables each time and perhaps you could place some in global scope such as the RegEx statements. I also removed the loop as i don't think you need to loop over everything 5 times to check.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
</head>
<body>
<form>
<div class="form-group">
<label for="inputName">Name</label>
<input type="text" class="form-control" id="inputName" placeholder="Enter name">
</div>
<div class="form-group">
<label for="inputName">Age</label>
<input type="text" class="form-control" id="inputAge" placeholder="Enter age">
</div>
<div class="form-group">
<label for="inputCity">City</label>
<input type="text" class="form-control" id="inputCity" placeholder="Enter city">
</div>
<div class="form-group">
<label for="InputEmail">Email address</label>
<input type="email" class="form-control" id="InputEmail" aria-describedby="emailHelp" placeholder="Enter email">
<!-- <small id="emailHelp" class="form-text text-muted">We'll never share your email with anyone else.</small> -->
</div>
<div class="form-group">
<label for="inputPhone">Phone number</label>
<input type="phone" class="form-control" id="inputPhone" placeholder="Phone number">
</div>
<button type="button" class="btn btn-primary submit">Submit</button>
<button type="button" class="btn btn-primary erase">Erase</button>
</form>
<script>
$(".btn.btn-primary.submit").click(function () {
let name_cityRegex = /^[a-zA-Z]+$/;
let emailRegex = /^(([^<>()\[\]\.,;:\s#\"]+(\.[^<>()\[\]\.,;:\s#\"]+)*)|(\".+\"))#(([^<>()[\]\.,;:\s#\"]+\.)+[^<>()[\]\.,;:\s#\"]{2,})$/i;
let age_phoneRegex = /^\d+$/;
let nameValue = $('#inputName').val();
let cityValue = $('#inputCity').val();
let ageValue = $('#inputAge').val();
let phoneValue = $('#inputPhone').val();
let nameResult = name_cityRegex.test(nameValue);
let cityResult = name_cityRegex.test(cityValue);
let ageResult = age_phoneRegex.test(ageValue);
let phoneResult = age_phoneRegex.test(phoneValue);
let mailValue = $('#InputEmail').val();
let mailResult = emailRegex.test(mailValue);
if (nameValue == '' || cityValue == '' || ageValue == '' || phoneValue == '' || mailValue == '') {
$('.alert.alert-danger').show();
}
else if (nameResult === false || cityResult === false) {
$('.alert.alert-danger').text("Please use letters only in the fields 'Name' and 'City'");
$('.alert.alert-danger').show();
return false;
}
else if (ageResult == false || phoneResult == false) {
$('.alert.alert-danger').text("Please use digits only in the fields 'Age' and 'Phone number'");
$('.alert.alert-danger').show();
return false;
}
else if (mailResult == false) {
$('.alert.alert-danger').text("Please enter a valid email adress");
$('.alert.alert-danger').show();
return false
}
return true;
// })
});
</script>
</body>
</html>

I don't really know why your tests gives you an error, but I think your $('.form-control').each is useless.
In this foreach you test all your fields for each field.
Maybe try without this foreach, just test all your fields when you click on the button by removing this bit of code :
$('.form-control').each(function () {
if ($(this).val() == "") {
$('.alert.alert-danger').show();
}
})
I don't see any other problem.

You have a syntax error I corrected that check below code.
function validateForm() {
var name_cityRegex = /^[a-zA-Z]+$/;
var emailRegex = /^(([^<>()\[\]\.,;:\s#\"]+(\.[^<>()\[\]\.,;:\s#\"]+)*)|(\".+\"))#(([^<>()[\]\.,;:\s#\"]+\.)+[^<>()[\]\.,;:\s#\"]{2,})$/i;
var age_phoneRegex = /^\d+$/;
var nameValue = $('#inputName').val();
var cityValue = $('#inputCity').val();
var ageValue = $('#inputAge').val();
var phoneValue = $('#inputPhone').val();
var nameResult = name_cityRegex.test(nameValue);
var cityResult = name_cityRegex.test(cityValue);
var ageResult = age_phoneRegex.test(ageValue);
var phoneResult = age_phoneRegex.test(phoneValue);
var mailValue = $('#InputEmail1').val();
var mailResult = emailRegex.test(mailValue);
$('.form-control').each(function () {
if ($(this).val() == "") {
$('.alert.alert-danger').show();
}
else if (nameResult == false || cityResult == false) {
$('.alert.alert-danger').text("Please use letters only in the fields 'Name' and 'City'");
$('.alert.alert-danger').show();
return false;
}
else if (ageResult == false || phoneResult == false) {
$('.alert.alert-danger').text("Please use digits only in the fields 'Age' and 'Phone number'");
$('.alert.alert-danger').show();
return false;
}
else if (mailResult == false) {
$('.alert.alert-danger').text("Please enter a valid email adress");
$('.alert.alert-danger').show();
return false
}
return true;
});
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form>
<div class="form-group">
<label for="inputName">Name</label>
<input type="text" name="name" class="form-control" id="inputName" placeholder="Enter name">
</div>
<div class="form-group">
<label for="inputName">Age</label>
<input type="text" name="age" class="form-control" id="inputAge" placeholder="Enter age">
</div>
<div class="form-group">
<label for="inputCity">City</label>
<input type="text" name="city" class="form-control" id="inputCity" placeholder="Enter city">
</div>
<div class="form-group">
<label for="InputEmail1">Email address</label>
<input type="text" name="email" class="form-control" id="InputEmail1" aria-describedby="emailHelp" placeholder="Enter email">
</div>
<div class="form-group">
<label for="inputPhone">Phone number</label>
<input type="text" name="phone" class="form-control" id="inputPhone" placeholder="Phone number">
</div>
<button type="button" class="btn btn-primary submit" onClick="validateForm()">Submit</button>
<button type="button" class="btn btn-primary erase">Erase</button>
</form>