Develop Reference

on click the result appears then auto refreshes

document.querySelector('.login').addEventListener('click', function() {
const check = document.querySelector('.username').value;
console.log(typeof check);
if (!check) {
document.querySelector('.errorMessage').textContent =
'kindly enter your username';
}
});
<div class="user-login">
<form>
<label for="">User Name : <input type="text" name="userName" class=" username"></label> <br>
<label for="">Password: <input type="password" name="" class="password"></label> <br>
<button class="login">Login</button>
</form>
</div>
<div class="errorMessage">
<label for=""></label> <br>
</div>

To your html modify the button like this:
<button type="button" class="login">Login</button>
or in your javascript you can do something like this:
document.querySelector('.login').addEventListener('click', function(e) {
e.preventDefault(); // Add this after set 'e' as parameter
const check = document.querySelector('.username').value;
console.log(typeof check);
if (!check) {
document.querySelector('.errorMessage').textContent =
'kindly enter your username';
}
});

JavaScript can not get alert box

So basically, I'm trying to do client side validation through JavaScript, but the code does not seem to be working. I am not getting any alert box. Below is HTML Form and JavaScript. I have skipped html and Body tags for obvious reasons. Can someone look over and see where am I making a mistake?
HTML form
<div class="container" >
<h1 style="text-align: center;">Online Vaccine Registration Form</h1>
<h1 style="text-align: center;">Developed by yourname</h1>
<form method="post" name="vacform" onsubmit=" return validateForm()">
<table>
<div class="row">
<div class="form-group col-md-6">
<label for="Name">Name : </label>
<input type="text" class="form-control" name="name" placeholder="Name">
</div>
<div class="form-group col-md-6">
<label for="CNIC" >CNIC : </label>
<input type="text" class="form-control" name="CNIC" placeholder="CNIC">
</div>
</div>
<div class="row">
<div class="form-group col-md-6">
<label for="Mob">Mobile : </label>
<input type="number" class="form-control" name="Mob" placeholder="Mobile">
</div>
<div class="form-group col-md-6">
<label for="Dob" >DoB : </label>
<input type="date" class="form-control" name="DoB">
</div>
</div>
<div class="form-group">
<label for="cen">Nearby centre</label>
<select class="form-control" id="sel1">
<option selected disabled>Select your Nearest Centre</option>
<option>Karachi West</option>
<option>Karachi East</option>
<option>Karachi North</option>
<option>Karachi Central</option>
<option>Malir</option>
</select>
</div>
</table>
<button type="button" class="btn btn-primary">Submit</button>
</form>
</div>
JavaScript
function validateForm()
{
var varname = document.vacform.name.value;
var varcnic = document.vacform.CNIC.value;
var varMob = document.vacform.Mob.value;
var varDoB = new Date(DoB);
var limitdate = new Date('2010-01-01');
var CNlength = 13;
var num = /^[0-9]+$/;
var str = /^[A-Za-z]+$/;
if(document.vacform.name.value!="")
{
if(document.vacform.CNIC.value!="")
{
if(document.vacform.Mob.value!="")
{
if(document.vacform.DoB.value!="")
{
if(varname.match(str))
{
if(varcnic.lenght == CNlength)
{
if(varcnic.match(num))
{
if(varDoB.getYear() < limitdate.getYear())
{
alert("All types of Validations have been done")
return true;
}
else
{
alert("Date should be less than 01-01-2010")
return false;
}
}
else
{
alert("CNIC field should have numbers only")
return false;
}
}
else
{
alert("CNIC lenght should be 13")
return false;
}
}
else
{
alert("Name can only contain letters")
return false;
}
}
else
{
alert("Date of Birth must be entered")
return false;
}
}
else
{
alert("Please Enter your mobile number")
return false;
}
}
else
{
alert("CNIC number Required")
return false;
}
}
else
{
alert("Name field can not be empty")
return false;
}
}
</script>

You call the function from the onsubmit event handler, however you never submit the form so it can't be triggered.
<button type="button" class="btn btn-primary">Submit</button>
This kind of button is for hooking JS into. It isn't a submit button.
Set type="submit" or remove the type attribute entirely (submit is the default).
Also address the errors in your HTML that a validator would highlight.

Check input field is empty or not

I am going to create simple validation form using Vanilla JavaScript, but I have problem, I want to check first ('entername') field, if user will not enter any letters in it, i want to console log message ('enter name'), it's works fine, but after that user reenter his name if field it returns in console ('enter name'), i want to return ('not enter') message.
var userBtn = document.getElementById('checkuserinputs');
var checkUserName = document.getElementById('user-name').value;
var checkUserSurname = document.getElementById('user-surname').value;
var checkUserPhone = document.getElementById('user-mobile').value;
userBtn.addEventListener('click', function(){
if(checkUserName.length == 0){
console.log('enter name')
}else{
console.log('not enter')
}
})
<div class="container-fluid">
<div class="modal-costum-row">
<div class="enter-name-side">
<div class="input-row">
<input class="costum--input" type="text" id="user-name" name="user-nm" placeholder="entername">
</div>
</div>
<div class="enter-surname-side">
<div class="input-row">
<input class="costum--input" type="text" id="user-surname" name="surname" placeholder="entersurname">
</div>
</div>
</div>
<div class="enter-tel-numb-side">
<div class="input-row input--wide">
<input class="costum--input" type="tel" id="user-mobile" name="user-mobile" placeholder="enterphonenumber">
</div>
</div>
</div>
<button id="checkuserinputs">check input</button>

You need to get the value after clicking the button. If you put it outside of the click event, the value will never be updated.
var userBtn = document.getElementById('checkuserinputs');
userBtn.addEventListener('click', function () {
var checkUserName = document.getElementById('user-name').value;
var checkUserSurname = document.getElementById('user-surname').value;
var checkUserPhone = document.getElementById('user-mobile').value;
if (checkUserName.length == 0) {
console.log('enter name')
} else {
console.log('not enter')
}
})
<div class="container-fluid">
<div class="modal-costum-row">
<div class="enter-name-side">
<div class="input-row">
<input class="costum--input" type="text" id="user-name" name="user-nm" placeholder="entername" />
</div>
</div>
<div class="enter-surname-side">
<div class="input-row">
<input class="costum--input" type="text" id="user-surname" name="surname" placeholder="entersurname" />
</div>
</div>
</div>
<div class="enter-tel-numb-side">
<div class="input-row input--wide">
<input class="costum--input" type="tel" id="user-mobile" name="user-mobile" placeholder="enterphonenumber" />
</div>
</div>
</div>
<button id="checkuserinputs">check input</button>

You need to retrieve the value of the input field in the click function callback:
userBtn.addEventListener('click', () => {
const checkUserName = document.getElementById('user-name').value;
if(checkUserName.length === 0){
console.log('enter name')
} else {
console.log('not enter')
}
})

change the variable geting value to button click function that is,
var userBtn = document.getElementById('checkuserinputs');
userBtn.addEventListener('click', function(){
var checkUserName = document.getElementById('user-name').value;
var checkUserSurname = document.getElementById('user-surname').value;
var checkUserPhone = document.getElementById('user-mobile').value;
if(!checkUserName){
console.log('enter name')
}else{
console.log('not enter')
}
})
var userBtn = document.getElementById('checkuserinputs');
userBtn.addEventListener('click', function(){
var checkUserName = document.getElementById('user-name').value;
var checkUserSurname = document.getElementById('user-surname').value;
var checkUserPhone = document.getElementById('user-mobile').value;
if(!checkUserName){
console.log('enter name')
}else{
console.log('not enter')
}
})
<div class="container-fluid">
<div class="modal-costum-row">
<div class="enter-name-side">
<div class="input-row">
<input class="costum--input" type="text" id="user-name" name="user-nm" placeholder="entername">
</div>
</div>
<div class="enter-surname-side">
<div class="input-row">
<input class="costum--input" type="text" id="user-surname" name="surname" placeholder="entersurname">
</div>
</div>
</div>
<div class="enter-tel-numb-side">
<div class="input-row input--wide">
<input class="costum--input" type="tel" id="user-mobile" name="user-mobile" placeholder="enterphonenumber">
</div>
</div>
</div>
<button id="checkuserinputs">check input</button>

While trying to hide submit button until all input fields are valid it is hiding only for the first text filed validation?

Working on form validation i'am trying to hide submit button until all text and password fields are not null and satisfies all input validation, but the problem is, it is enabling the submit button for the first text field validation only.
So what's wrong with my code, please correct me.,
Here's the code:
$(document).ready(function() {
var error_firstName = false;
var error_lastName = false;
var error_emailAdd = false;
var error_pass = false;
var error_confirmPass = false;
var error_mobile = false;
var error_confirmMob = false;
$("#error_form_firstName").hide();
$("#error_form_lastName").hide();
$("#error_form_emailAdd").hide();
$("#error_form_password").hide();
$("#error_span").hide();
$("#error_form_confirmPassword").hide();
$("#error_form_mobile").hide();
$("error_form_confirmNumber").hide();
$("#formSubmit").attr("disabled", "disabled");
$("#form_firstName").focusout(function() {
check_FirstName();
});
$("#form_lastName").focusout(function() {
check_LastName();
});
$("#form_email").focusout(function() {
check_email();
});
$("#form_pass").focusout(function() {
check_password();
});
$("#form_cPass").focusout(function() {
check_confirm_password();
});
$("#form_mob").focusout(function() {
check_Mobile();
});
$("#form_cMob").focusout(function() {
check_cMobile();
});
$('input, password').change(function(){
if(error_firstName == false && error_lastName == false && error_emailAdd == false && error_pass == false && error_confirmPass == false && error_mobile == false && error_confirmMob == false){
$("input[type=submit]").removeAttr("disabled");
return true;
}
else{
alert("Please fill the form correctly");
return false;
}
});
});
Corresponding HTML code for form validation:
<form:form id="reg_form" action="submitRegistration.do" method="POST"
commandName="registrationForm">
<div class="col-md-6 col-md-offset-3 register-top-grid">
<h3>Please fill the below information</h3>
<div>
<span>First Name</span>
<form:input id="form_firstName" path="firstName" />
<form:errors path="firstName" cssStyle="color:red" element="div" />
<p id="error_form_firstName" class="errorMessage"></p>
</div>
<div>
<span>Last Name</span>
<form:input id="form_lastName" path="lastName" />
<form:errors path="lastName" cssStyle="color:red" element="div" />
<p id="error_form_lastName" class="errorMessage"></p>
</div>
<div>
<span>Email Address</span>
<form:input id="form_email" path="email" />
<form:errors path="email" cssStyle="color:red" element="div" />
<p id="error_form_emailAdd" class="errorMessage"></p>
</div>
<div>
<span>Password</span>
<form:password id="form_pass" path="password" />
<form:errors path="password" cssStyle="color:red" element="div" />
<p id="error_form_password" class="errorMessage"></p>
<!-- This is for extra line after password for alignment of error_text -->
<p id="error_span" class="errorMessage"></p>
</div>
<div>
<span>Confirm Password</span>
<form:password id="form_cPass" path="confirmPassword" />
<form:errors path="confirmPassword" cssStyle="color:red" element="div" />
<p id="error_form_confirmPassword" class="errorMessage"></p>
</div>
<div>
<span>Mobile Number</span>
<form:input id="form_mob" path="mobile" />
<form:errors path="mobile" cssStyle="color:red" element="div" />
<p id="error_form_mobile" class="errorMessage"></p>
</div>
<div>
<span>Confirm Mobile Number</span>
<form:input id="form_cMob" path="confirmMobile" />
<form:errors path="confirmMobile" cssStyle="color:red" element="div" />
<p id="error_form_confirmNumber" class="errorMessage"></p>
</div>
<div style="text-align: center">
<input id="formSubmit" type="submit" value="submit" /> <button id="clear" type="button" value="clear" />
</div>
<a class="news-letter" href="#"> <label class="checkbox">
<input type="checkbox" name="checkbox" checked=""><i> </i>Sign Up for Newsletter</label>
</a>
</div>
<div class="clearfix"></div>
</form:form>

IF I am reading this correctly, you have a function for each input to check THAT ONE INPUT when you focus out. Now assume you have First Name and it is OK after entry - your 'Last Name' has not yet been entered/checked; yet you have negative errors (all set false) by default. I would suggest to set them all to true instead - so that they are all entered before the submit gets enabled. I make assumption that all elements are required.
Optionally, on one "focusout", trigger that focusout event on ALL of them, but that is a good bit of extra code on each focus out.
Another option would be to have a "validateform" function and use that for all of them i.e.
var error_firstName = true;
var error_lastName = true;
var error_emailAdd = true;
var error_pass = true;
var error_confirmPass = true;
var error_mobile = true;
var error_confirmMob = true;
function validateform(){
check_FirstName();
check_LastName();
check_email();
// the others in here...
// now do this
var hasErrors = error_firstName
|| error_lastName
|| error_emailAdd
|| error_pass
|| error_confirmPass
|| error_mobile
|| error_confirmMob;
if(hasErrors){alert("Please fill the form correctly");}
$("#formSubmit").prop("disabled", hasErrors");
return hasErrors;
}
// add others in here
$("#form_firstName,#form_lastName,#form_email")
.on("focusout change",validateform);
Note you could also do a bulk show/hide of your error things like this:
function displayErrorThings(){
$("#error_form_firstName").toggle(error_firstName);
$("#error_form_lastName").toggle(error_lastName);
$("#error_form_emailAdd").toggle(error_emailAdd);
$("#error_form_password").toggle(error_pass);
$("#error_span").toggle(error_pass);
$("#error_form_confirmPassword").toggle(error_confirmPass);
$("#error_form_mobile").toggle(error_mobile);
$("error_form_confirmNumber").toggle(error_confirmMob);
}
Thus just call it in the same validation function above (and on initial start)
displayErrorThings()

form validation problems with jquery / javascript

This is my first real project which involves form validation. I am experiancing a problem which I can not find the solution to.
The objective is this, there is a continue button which will be activated once all the field inputs have been passed as valid. I am going about this by creating seperate variables, all initially set as false, devoted to checking each input field. When the user has entered correct validation data, the variable is set to true.
I then run an if statement to check if all the variables are set to true, and if so, I activate the continue button which, when clicked, slides the next part of the form into the page.
HTML:
<div class="container">
<h3>Step 3: Your Details</h3>
<!-- SLIDE-IN DIV TO REPRESENT DAY PASS -->
<div class="row chosenmembership">
<div class="col-md-12 text-center" id="yourdetails">
<form action="" method="">
<div class="form-group">
<label for="email">Email:</label>
<input type="text" placeholder="Email Address" id="email" class="form-control your-details">
<span class="warning" id="email-warning"></span>
</div>
<div class="form-group">
<label for="name">Name:</label>
<input type="text" placeholder="Full Name" id="name" class="form-control your-details">
<span class="warning" id="name-warning"></span>
</div>
<div class="form-group">
<label for="number">Contact Number:</label>
<input type="text" placeholder="Contact Number" id="number" class="form-control your-details">
<span class="warning" id="number-warning"></span>
</div>
<div class="form-group">
<label for="dob">Date of Birth:</label>
<input type="date" id="dob" class="form-control your-details">
<span class="warning" id="dob-warning"></span>
</div>
</form>
<input type="submit" id="submit" value="CONTINUE">
</div>
</div>
</div>
JAVASCRIPT / JQUERY:
//collection of input form fields//
var formSubmit = $("#submit");
var emailField = $("#email");
var nameField = $("#name");
var numberField = $("#number");
//Switch to true when each validation has passed//
emailValidated = false;
nameValidated = false;
numberValidated = false;
//email validation check//
emailField.on("input",function(){
var emailInput = $(this).val()
var testExp = new RegExp(/[a-z0-9._%+-]+#[a-z0-9.-]+\.[a-z]{2,3}$/);
if (emailInput < 1) {
$("#email-warning").html("Email is required!");
$("#email-warning").css("visibility","visible");
emailValidated = false;
}
else if (!testExp.test(emailInput)){
$("#email-warning").html("Please enter a valid email");
$("#email-warning").css("visibility","visible");
emailValidated = false;
} else {
$("#email-warning").css("visibility","hidden");
emailValidated = true;
}
})
//name validation check//
nameField.on("input",function(){
var nameInput = $(this).val()
if (nameInput < 1) {
$("#name-warning").html("Name is required");
$("#name-warning").css("visibility","visible");
nameValidated = false;
} else {
$("#name-warning").css("visibility","hidden");
nameValidated = true;
}
})
//contact number validation check//
numberField.on("input",function(){
var numberInput = $(this).val()
if (typeof numberInput !== "number" && numberInput.length < 9) {
$("#number-warning").html("Please enter a valid number");
$("#number-warning").css("visibility","visible");
numberValidated = false;
} else {
$("#number-warning").css("visibility","hidden");
numberValidated = true;
}
})
if (emailValidated && nameValidated && numberValidated){
alert("correct");
}
})
at the moment, I am simply using the alert prompt to test if it is working, but it fails.
As mentioned, this is my first real form validation. Any other tips or advice would be greatly appreciated. Thanks for the help in advance.

There were a couple things that I found from copying pasting your snippets of code. 1 there was an ending "})" without a beginning $(document).ready(function(){ ". 2 none of your ".on" statements had an ending semi colon.
Here is my javascript with a small change
$(document).ready(function () {
//collection of input form fields//
var formSubmit = $("#submit");
var emailField = $("#email");
var nameField = $("#name");
var numberField = $("#number");
//Switch to true when each validation has passed//
emailValidated = false;
nameValidated = false;
numberValidated = false;
//email validation check//
emailField.on("input", function () {
var emailInput = $(this).val()
var testExp = new RegExp(/[a-z0-9._%+-]+#[a-z0-9.-]+\.[a-z]{2,3}$/);
if (emailInput < 1) {
$("#email-warning").html("Email is required!");
$("#email-warning").css("visibility", "visible");
emailValidated = false;
}
else if (!testExp.test(emailInput)) {
$("#email-warning").html("Please enter a valid email");
$("#email-warning").css("visibility", "visible");
emailValidated = false;
} else {
$("#email-warning").css("visibility", "hidden");
emailValidated = true;
enableContinue();
}
});
//name validation check//
nameField.on("input", function () {
var nameInput = $(this).val()
if (nameInput < 1) {
$("#name-warning").html("Name is required");
$("#name-warning").css("visibility", "visible");
nameValidated = false;
} else {
$("#name-warning").css("visibility", "hidden");
nameValidated = true;
enableContinue();
}
});
//contact number validation check//
numberField.on("input", function () {
var numberInput = $(this).val()
if (typeof numberInput !== "number" && numberInput.length < 9) {
$("#number-warning").html("Please enter a valid number");
$("#number-warning").css("visibility", "visible");
numberValidated = false;
} else {
$("#number-warning").css("visibility", "hidden");
numberValidated = true;
enableContinue();
}
});
enableContinue = function () {
if (emailValidated && nameValidated && numberValidated) {
$('#submit').prop('disabled', false);
}
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container">
<h3>Step 3: Your Details</h3>
<!-- SLIDE-IN DIV TO REPRESENT DAY PASS -->
<div class="row chosenmembership">
<div class="col-md-12 text-center" id="yourdetails">
<form action="" method="">
<div class="form-group">
<label for="email">Email:</label>
<input type="text" placeholder="Email Address" id="email" class="form-control your-details">
<span class="warning" id="email-warning"></span>
</div>
<div class="form-group">
<label for="name">Name:</label>
<input type="text" placeholder="Full Name" id="name" class="form-control your-details">
<span class="warning" id="name-warning"></span>
</div>
<div class="form-group">
<label for="number">Contact Number:</label>
<input type="text" placeholder="Contact Number" id="number" class="form-control your-details">
<span class="warning" id="number-warning"></span>
</div>
<div class="form-group">
<label for="dob">Date of Birth:</label>
<input type="date" id="dob" class="form-control your-details">
<span class="warning" id="dob-warning"></span>
</div>
</form>
<input type="submit" class="btn btn-primary" id="submit" disabled="disabled" value="CONTINUE">
</div>
</div>
</div>
Your form CONTINUE button becomes enables once all fields have a value. Note: I did not try to improve your javascript any, just made it work.

Right now you synchronically check validation variables at script, so they are all false. You have to asynchronically check them after form submit. Just add event listener to form submit to check variables like this:
document.getElementById('#form').addEventListener('submit', function(){
if (emailValidated && nameValidated && numberValidated){
alert("correct");
}
});
Don't forget to set id to your form.

You may be able to save a lot of work if you leverage some of the built in HTML5 form validation. https://developer.mozilla.org/en-US/docs/Learn/HTML/Forms/Form_validation
This simple example adds a new field every time you submit the form, as long as the existing fields are valid. You would need to test the state of the form to see if you should be adding another section or submitting.
$('form').on('submit', function() {
$(this).find('fieldset').append('<input type="text" required />');
return false;
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form>
<fieldset>
<input type="text" required />
</fieldset>
<input type="submit" id="submit" value="continue" />
</form>