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how to get external form validation to work with jQuery

Okay, I'm trying to get a contact form to work and it is, sort of. The data is passing through, but I can't get the jQuery to work. If I type in two different email addresses it doesn't catch it. Here is the relevant code I used:
HTML
<aside>
<form action="sendmail.php" method="post" name="contact_form" id="contact_form">
<fieldset>
<legend>sign up now!</legend><br>
<p>Sign up for my email list and get a free mini coloring book!</p><br>
<img src="Images/minicoloirngbook.jpg" alt="mini coloring book"><br>
<label for="name"> Name:</label>
<input type="text"name="name" id="name" required><span>*</span><br>
<label for="email">Email Address:</label>
<input type="email" name="email" id="email" required><span>*</span><br>
<label for="verify">Verify Email:</label>
<input type="email" name="verify" id="verify" required> <span>*</span><br>
<div id="buttons">
<input type="submit" id="submit" value="Sign Up">
</div>
</fieldset>
</form>
</aside>
and here is the Javascript:
$("#contact_form").submit(event => {
let isValid = true;
// validate the first name entry
const name = $("#name").val().trim();
if (name == "") {
$("#name").next().text("This field is required.");
isValid = false;
} else {
$("#name").next().text("");
}
$("#name").val(name);
// validate the email entry with a regular expression
const emailPattern = /\b[A-Za-z0-9._%+-]+#[A-Za-z0-9.-]+\.[A-Za-z]{2,4}\b/;
const email = $("#email").val().trim();
if (email == "") {
$("#email").next().text("This field is required.");
isValid = false;
} else if ( !emailPattern.test(email) ) {
$("#email").next().text("Must be a valid email address.");
isValid = false;
} else {
$("#email").next().text("");
}
$("#email").val(email);
// validate the verify entry
const verify = $("#verify").val().trim();
if (verify == "") {
$("#verify").next().text("This field is required.");
isValid = false;
} else if (verify !== email) {
$("#verify").next().text("Must match first email entry.");
isValid = false;
} else {
$("#verify").next().text("");
}
$("#verify").val(verify);
// prevent the submission of the form if any entries are invalid
if (isValid == false) {
event.preventDefault();
}
}),
I think that the answer is probably something really simple that I can't see and would appreciate your help in figuring it out.

This should do it. Here is the jsfiddle if you like to play with the code: https://jsfiddle.net/bogatyr77/xk6ez3aq/7/
$("form").submit(function(e) {
var name = $("#a").val();
if (name == "") {
$("#nameerror").text("This field is required.");
alert('false');
} else {
alert('true');
$("#nameerror").remove();
}
//email1
var emailPattern = /\b[A-Za-z0-9._%+-]+#[A-Za-z0-9.-]+\.[A-Za-z]{2,4}\b/;
const email = $("#b").val();
if (email == "") {
$("#email1error").text("This field is required.");
isValid = false;
} else if (!emailPattern.test(email)) {
$("#email1error").text("Must be a valid email address.");
isValid = false;
} else {
$("#email1error").remove();
}
//eamil 2
var verify = $("#c").val();
if (verify == "") {
$("#email2error").text("This field is required.");
isValid = false;
} else if (verify !== email) {
$("#email2error").text("Must match first email entry.");
isValid = false;
} else {
$("#email2error").remove();
}
if (isValid == false) {
event.preventDefault();
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form action="javascript:alert('ok')">
<label for="name"> Name:</label>
<input type="text" name="name" id="a"><span>*</span>
<div id="nameerror"></div><br>
<label for="email">Email Address:</label>
<input type="text" name="email" id="b"><span>*</span>
<div id="email1error"></div><br>
<label for="verify">Verify Email:</label>
<input type="text" name="verify" id="c"> <span>*</span>
<div id="email2error"></div><br>
<input type="submit" value="submit" />
</form>
<div></div>

The id-selector does not work within php

my javascript won't respond to my id-tag within php code:
else {
echo '<form = "nav-login" method="post" onsubmit="return noEmptyUserFields();" action="includes/login.inc.php">
<input type="text" id="uidz" name="uid" placeholder="Username/e-mail">
<input type="password" id="pwdz" name="pwd" placeholder="password">
<button type="submit" name="submit">Login</button>
</form>
Sign up';
}
But it responds to my javascript which is outside of the php which looks like this:
<form class="signup-form" method="post" onsubmit="return noEmptyUserFields();" action="includes/signup.inc.php">
<input type="text" id="first" name="first" placeholder="Firstname">
<input type="text" id="last" name="last" placeholder="Lastname" >
<input type="email" id="email" name="email" placeholder="E-mail" >
<input type="text" id="uid" name="uid" placeholder="Username" >
<input type="password" id="pwd" name="pwd" placeholder="Password" ></p2>
<button type="submit" name="submit">Sign up</button></form>
How come it won't respond to the id-selector within php?
I have included <script src="includes/javascript.js"></script>
on both.
My javascript looks like this (noEmptyLoginFields) :
if (email.trim().length < 1)
{
alert('Email must be filled out');
return false;
}
else if(pwd.trim().length < 6)
{
alert('Password must contain atleast 6 characters');
return false;
}
else if (first.trim().length < 1)
{
alert('First name must be filled out');
return false;
}
else if (last.trim().length < 1)
{
alert('Last name must be filled out');
return false;
}
else if (uid.trim().length < 1)
{
alert('Username must be filled out');
return false;
}
else return true;
}
function noEmptyLoginFields()
var uidz = document.getElementById('uidz').value;
var pwdz = document.getElementById('pwdz').value;
if (uidz.trim().length < 1)
{
alert('Username and password must be filled out!');
return false;
}
else if(pwdz.trim().length < 1)
{
alert('Username and password must be filled out!');
return false;
}
}

You seem to be using the same function name for both form validations, which is causing the error. I advise you to handle form validation purely in javascript using event handlers:
document.querySelector("#formId").addEventListener("submit", function() {
// if(...) return false;
});

How to print error message under respective input field using javascript validation in php [closed]

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Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 6 years ago.
Improve this question
How to print error message under respective input field if left empty and error message must be removed when filled, how to proceed further i have not used javascript for validation earlier.
script code
function validateForm() {
var a = document.forms["student_reg"]["name"].value;
if (a == null || a == "") {
alert("Name must be filled out");
return false;
}
var b = document.forms["student_reg"]["email"].value;
if (b == null || b == "") {
alert("Email must be filled out");
return false;
}
var c = document.forms["student_reg"]["username"].value;
if (c == null || c == "") {
alert("Username must be filled out");
return false;
}
var d = document.forms["student_reg"]["password"].value;
if (d == null || d == "") {
alert("Password must be filled out");
return false;
}
var e = document.forms["student_reg"]["roll_no"].value;
if (e == null || e == "") {
alert("Roll no must be filled out");
return false;
}
}
html code is here
<body>
Login
<form name="student_reg" method="POST" action="" onsubmit="return validateForm()">
<p>NAME:</p>
<input type="text" name="name" value="" >
<span class="error"><p id="name_error"></p></span>
<p>EMAIL:</p>
<input type="text" name="email" value="" >
<span class="error"><p id="email_error"></p></span>
<p>USERNAME:</p>
<input type="text" name="username" value="" >
<span class="error"><p id="username_error"></p></span>
<p>PASSWORD:</p>
<input type="password" name="password" value="" >
<span class="error"><p id="password_error"></p></span>
<p>ROLL NO:</p>
<input type="number" name="roll_no" value="" >
<span class="error"><p id="roll_no_error"></p></span>
<br/>
<br/>
<br/>
<input type="submit" name="submit" value="submit">
</form>
</body>

You can try this code:
It will check errors and returns at last after displaying all error messages if any.
function validateForm() {
var error = 0;
var a = document.forms["student_reg"]["name"].value;
document.getElementById('name_error').innerHTML = '';
if (a == null || a == "") {
// alert("Name must be filled out");
error++;
document.getElementById('name_error').innerHTML = 'Name must be filled out';
}
var b = document.forms["student_reg"]["email"].value;
document.getElementById('email_error').innerHTML = '';
if (b == null || b == "") {
// alert("Email must be filled out");
error++;
document.getElementById('email_error').innerHTML = 'Email must be filled out';
}
var c = document.forms["student_reg"]["username"].value;
document.getElementById('username_error').innerHTML = '';
if (c == null || c == "") {
// alert("Username must be filled out");
error++;
document.getElementById('username_error').innerHTML = 'Username must be filled out';
}
var d = document.forms["student_reg"]["password"].value;
document.getElementById('password_error').innerHTML = '';
if (d == null || d == "") {
// alert("Password must be filled out");
error++;
document.getElementById('password_error').innerHTML = 'Password must be filled out';
}
var e = document.forms["student_reg"]["roll_no"].value;
document.getElementById('roll_no_error').innerHTML = '';
if (e == null || e == "") {
// alert("Roll no must be filled out");
error++;
document.getElementById('roll_no_error').innerHTML = 'Roll no must be filled out';
}
if(error>0) {
return false;
}
return true;
}

Keep all the name attributes in array and validate in loop. As your ID is related to name attribute, concatenate the name with _error to get the ID of the error placeholder.
function validateForm() {
var names = ['name', 'email', 'username', 'password', 'roll_no'];
var errorCount = 0;
names.forEach(function(el) {
var val = document.forms["student_reg"][el].value;
if (val == null || val == "") {
document.getElementById(el + '_error').textContent = el.toUpperCase().replace('_', ' ') + " must be filled out";
++errorCount;
}
});
if (errorCount) return false;
}
<form name="student_reg" method="POST" action="" onsubmit="return validateForm()">
<p>NAME:</p>
<input type="text" name="name" value="">
<span class="error"><p id="name_error"></p></span>
<p>EMAIL:</p>
<input type="text" name="email" value="">
<span class="error"><p id="email_error"></p></span>
<p>USERNAME:</p>
<input type="text" name="username" value="">
<span class="error"><p id="username_error"></p></span>
<p>PASSWORD:</p>
<input type="password" name="password" value="">
<span class="error"><p id="password_error"></p></span>
<p>ROLL NO:</p>
<input type="number" name="roll_no" value="">
<span class="error"><p id="roll_no_error"></p></span>
<br/>
<br/>
<br/>
<input type="submit" name="submit" value="submit">
</form>

You can iterate through all elements of the form student_reg to validate email and required and print error message under respective input field if no value was set:
const validateForm = () => {
const form = document.forms['student_reg'],
inputs = [...form.getElementsByTagName('input')],
errors = [...form.getElementsByClassName('error')],
regex = /\S+#\S+\.\S+/,
setErrorMsg = (str, msg) => `${str.replace('_', ' ')} ${msg}`
let countErrors = 0
inputs.forEach((input, index) => {
// clear all errors
(errors[index] || '').innerHTML = ''
// validate email
if (input.name === 'email' && !regex.test(input.value)) {
errors[index].innerText = setErrorMsg(input.name, 'should be valid')
countErrors++
}
// validate required
if (!input.value) {
errors[index].innerText = setErrorMsg(input.name, 'field is required')
countErrors++
}
})
return countErrors === 0
}
p {
font-size: 13px;
margin: 4px 0 0;
}
.error {
font-size: 12px;
padding: 6px 0 4px;
color: red;
display: block
}
.error:first-letter {
text-transform: uppercase
}
button {
margin-top: 8px;
font-size: 16px;
}
<form name="student_reg" method="POST" action="" onsubmit="return validateForm()">
<p>NAME:</p>
<input type="text" name="name" value="">
<span class="error"></span>
<p>EMAIL:</p>
<input type="text" name="email" value="">
<span class="error"></span>
<p>USERNAME:</p>
<input type="text" name="username" value="">
<span class="error"></span>
<p>PASSWORD:</p>
<input type="password" name="password" value="">
<span class="error"></span>
<p>ROLL NO:</p>
<input type="number" name="roll_no" value="">
<span class="error"></span>
<button>Submit</button>
</form>

simple form It hold the Span for the Error msg.The span Id is very important here.you need to make color for errors using css
<form id="loginform" name="loginform" action="" method="post">
<label>Name</label>
<input type="text" name="username" />
<p></p>
<span id="usernameError"></span>
<p></p>
<label>Pwd</label>
<input type="password" name="password" />
<p></p>
<span id="passwordError"></span>
<p></p>
<input type="submit" value="Submit" />
</form>
script
<script type="application/javascript">
window.onload = function(){
function handleinput(){
if(document.loginform.username.value == ""){
document.getElementById("usernameError").innerHTML = "You must enter a username";
return false;
}
if(document.loginform.password.value == ""){
document.getElementById("passwordError").innerHTML = "You must enter a password";
return false;
}
}
document.getElementById("loginform").onsubmit = handleinput;
}
</script>

use flag to 'continue' in javascript?

I want to trigger submit_form function only after all fields are filled. Now the submit form will got triggered.
$('#submit').click(function() {
$('body input').each(function() {
if ($(this).val() == '') {
alert('Please fill in ' + $(this).attr('placeholder'));
$(this).focus();
return false;
}
})
submit_form();
});
function submit_form() {
alert('proceed to sumbit form.');
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<body>
<input type="" placeholder="name">
<br>
<br>
<input type="text" placeholder="hp">
<br>
<br>
<input type="text" placeholder="email">
<br>
<br>
<button id="submit">Submit</button>
</body>

ok, according to your code your submit functions always calls so i have added a flag for it please check....
$('#submit').click(function() {
var flag = 1;
$('body input').each(function() {
if ($(this).val() == '')
{
alert('Please fill in ' + $(this).attr('placeholder'));
$(this).focus();
flag = 0;
return false;
}
})
if(flag)
{
submit_form();
}
});

try this
$('#submit').click(function() {
var flag = 1;
$('body input').each(function() {
if ($(this).val() == '')
{
alert('Please fill in ' + $(this).attr('placeholder'));
$(this).focus();
flag = 0;
return false;
}
else
{
flag = 1;
}
})
if(flag)
{
submit_form();
}
});
function submit_form() {
alert('proceed to sumbit form.');
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<body>
<input type="" placeholder="name">
<br>
<br>
<input type="text" placeholder="hp">
<br>
<br>
<input type="text" placeholder="email">
<br>
<br>
<button id="submit">Submit</button>
</body>

Use a flag to prevent submitting your form when one input field is empty.
$('#submit').click(function() {
this.canSend = true;
$('body input').each(function() {
if ($(this).val() == '') {
this.canSend = false;
alert('Please fill in ' + $(this).attr('placeholder'));
$(this).focus();
return false;
}
})
if (this.canSend) {
submit_form();
}
});
function submit_form() {
alert('proceed to sumbit form.');
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="" placeholder="name">
<br>
<br>
<input type="text" placeholder="hp">
<br>
<br>
<input type="text" placeholder="email">
<br>
<br>
<button id="submit">Submit</button>
A refactored version also available here:
https://jsfiddle.net/j74u8wvL/

Remove all JavaScript.
<body>
<input type="text" placeholder="name" required>
<br>
<br>
<input type="text" placeholder="hp" required>
<br>
<br>
<input type="email" placeholder="email" required>
<br>
<br>
<button id="submit">Submit</button>
</body>

how to validate single field in form when i have 5 fields using javascript?

I have a form which has four fields, when the all the fields are empty and submit button is clicked- it should alert "Please select at least one value".
When I enter the value in any of the fields the form should get submitted. I tried the following code but it's not working
function validatefleid() {
var computername = document.myform.computername.value;
var monitorname = document.myform.monitorname.value;
var tvname = document.myform.tvname.value;
var laptopname = document.myform.laptopname.value;
var cellphonename = document.myform.cellphonename.value;
if ((computername == null || computername == "") || (monitorname == null || monitorname == "") || (tvname == null || tvname == "") || (laptopname == null || laptopname == "") || (cellphonename == null || cellphonename == "")) {
alert("Please atleast one value");
return false;
}
}
<form name="myform" onsubmit="return validatefleid()">
computer
<input type="text" class="form-control inpt-bx-txtclr-home" name="computername" id="computerid" placeholder="000">monitor
<input type="text" class="form-control inpt-bx-txtclr-home" name="monitorname" id="monitorid" placeholder="000">tv
<input type="text" class="form-control inpt-bx-txtclr-home" name="tvname" id="tvid" placeholder="000">laptop
<input type="text" class="form-control inpt-bx-txtclr-home" name="laptopname" id="laptopid" placeholder="000">cellphone
<input type="text" class="form-control inpt-bx-txtclr-home" name="cellphonename" id="cellphoneid" placeholder="000">
<button type="submit">Calculate</button>
</form>

It is possible by iterating through all of the inputs within the form, and look for at least one input with value that's different than ''. Check the demo:
$(function(){
var $form = $('#myform');
$form.submit(function(){
var valid = false;
$('input', $form).each(function(){
if($(this).val() != ''){
valid = true;
}
});
if (!valid) {
alert("Please atleast one value");
}
return valid;
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="myform" name="myform">
computer<input type="text" class="form-control inpt-bx-txtclr-home" name="computername" id="computerid" placeholder="000">
monitor<input type="text" class="form-control inpt-bx-txtclr-home" name="monitorname" id="monitorid" placeholder="000">
tv<input type="text" class="form-control inpt-bx-txtclr-home" name="tvname" id="tvid" placeholder="000">
laptop<input type="text" class="form-control inpt-bx-txtclr-home" name="laptopname" id="laptopid" placeholder="000">
cellphone<input type="text" class="form-control inpt-bx-txtclr-home" name="cellphonename" id="cellphoneid" placeholder="000">
<button type="submit" >Calculate</button>
</form>

Without jQuery :
https://jsfiddle.net/uL28jsf9/
<script type="text/javascript">
function validatefleid()
{
var allFieldsNames = ['computername', 'monitorname', 'tvname', 'laptopname', 'cellphonename'];
var checkIfFieldEmpty function(fieldName) {
var fieldValue = document.myform[fieldName].value;
return fieldValue === "" || fieldValue === null
}
var allFieldsEmpty = allFieldsNames.every(checkIfFieldEmpty);
if (allFieldsEmpty) {
alert("Please atleast one value");
return false;
}
else {
alert("I'm ok with that !")
}
}
</script>

oops i have got the answer
I have a form which as four fields when the all the fields are empty and submit button is clicked it should alert as "please select atleast one value" when i entry the value in any of the one fields the form should get submitted i have tries the following code but its not working
<script type="text/javascript">
function validatefleid()
{
var computername=document.myform.computername.value;
var monitorname=document.myform.monitorname.value;
var tvname=document.myform.tvname.value;
var laptopname=document.myform.laptopname.value;
var cellphonename=document.myform.cellphonename.value;
if((computername==null || computername=="") && (monitorname==null || monitorname=="") && (tvname==null || tvname=="") && (laptopname==null || laptopname=="") && (cellphonename==null || cellphonename==""))
{
alert("Please atleast one value");
return false;
}
}
</script>
<form name="myform" onsubmit="return validatefleid()">
computer<input type="text" class="form-control inpt-bx-txtclr-home" name="computername" id="computerid" placeholder="000">
monitor<input type="text" class="form-control inpt-bx-txtclr-home" name="monitorname" id="monitorid" placeholder="000">
tv<input type="text" class="form-control inpt-bx-txtclr-home" name="tvname" id="tvid" placeholder="000">
laptop<input type="text" class="form-control inpt-bx-txtclr-home" name="laptopname" id="laptopid" placeholder="000">
cellphone<input type="text" class="form-control inpt-bx-txtclr-home" name="cellphonename" id="cellphoneid" placeholder="000">
<button type="submit" >Calculate</button>
</form>

here is a complete cross-browser working version of validatefleid function.
function validatefleid(){
var inputIds = ['computerid','monitorid','tvid','laptopid','cellphoneid'];
var hasEnteredAnyValue = false;
for(var i=0;i<inputIds.length;i++){
hasEnteredAnyValue = document.getElementById(inputIds[i]).value;
if(hasEnteredAnyValue)break;
}
if(!hasEnteredAnyValue)
{
alert("Please atleast one value");
return false;
}
}