Develop Reference

Disabling a button on empty <select> list?

`I've created a form that allows a user to enter their details and have their first and last names displayed along with a numerical ID. There is a 'Delete' button allowing the user to remove whatever name they select.
by default, the 'Delete' button should be disabled until the <select> list is populated. If all names are deleted from the list - the 'Delete' button should disable again.
That's where im struggling. I cant get the 'Delete' button to enable when a name is added to the list.
Below is my HTML and JavaScript:
MemberList
<h1>Member List</h1>
<form method="post" id="_frmFull">
<label for="lstMembers">Member:</label>
<select size="10"
name="lstMembers"
id="lstMembers">
</select>
<button type="button"
id="addMember"
name="Add Member">
Add Member
</button>
<button type="button"
name="Delete Member"
id="delete">
Delete Member</button>
<div id="Modal" class="modal">
<div class="modal-form">
<label for="memTitle">Title:</label>
<input list="memTitles" name="memTitles" id="memTitle">
<datalist id="memTitles">
<option value="Dr">
<option value="Mr">
<option value="Mrs">
<option value="Ms">
</datalist>
<label for="firstName">First Name:</label>
<input type="text" name="firstName" id="firstName" required="required">
<label for="middleName">Middle Name (optional):</label>
<input type="text" name="middleName" id="middleName">
<label for="lastName">Last Name:</label>
<input type="text" name="lastName" id="lastName" required="required">
<br><br>
<label for="Country">Country:</label>
<input list="countries" name="Country" id="Country">
<datalist id="countries">
<option value="Australia">
<option value="United Kingdom">
<option value="America">
<option value="New Zealand">
</datalist>
<label for="Gender">Gender:</label>
<select name="Gender" id="Gender">
<option>Male</option>
<option>Female</option>
<option>Other</option>
</select>
<label for="birthDate">Birthdate:</label>
<input type="date"
id="birthDate"
min="1900-01-01"
max="2022-12-31" required="required">
<br><br>
<div id="resiAddress">
<p>Residential Address:</p>
<br>
<label for="txtResidentialAddress">Address:</label>
<input type="text" required="required" id="txtResidentialAddress" oninput="copyAddressFields();">
<br><br>
<label for="txtResiPostCode">Postcode:</label>
<input type="text" required="required" id="txtResiPostCode">
<br><br>
<label for="txtResiSuburb">Suburb:</label>
<input type="text" required="required" id="txtResiSuburb">
<br><br>
<label for="txtResiCountry" class="country">Country</label>
<input type="text" required="required" id="txtResiCountry">
<br><br>
<label for="txtResiState">State:</label>
<input type="text" required="required" id="txtResiState">
</div>
<br><br>
<label for="chkSynchronizeAddresses">Same as residential </label>
<input type="checkbox" required="required" id="chkSynchronizeAddresses" >
<div id="postAddress">
<p>Postal Address:</p>
<br>
<label for="txtPostalAddress">Address:</label>
<input type="text" id="txtPostalAddress">
<br><br>
<label for="txtPostCode">Postcode:</label>
<input type="text" id="txtPostCode">
<br><br>
<label for="txtPostalSuburb">Suburb:</label>
<input type="text" id="txtPostalSuburb">
<br><br>
<label for="txtPostalCountry">Country:</label>
<input type="text" id="txtPostalCountry">
<br><br>
<label for="txtPostalState">State:</label>
<input type="text" id="txtPostalState">
</div>
<br><br>
<label for="txtPhone" class="phone">Phone: (optional)</label>
<input id="txtPhone" type="text">
<br><br>
<label for="txtMobile" class="mobile">Mobile: (optional)</label>
<input id="txtMobile" type="text">
<br><br>
<button type="button" name="save" id="save">Save</button>
<br><br>
<button type="button"
name="cancel"
id="closeModal">
Cancel</button>
</div>
</div>
</form>
<script>
console.log("Log test - please work!!")
const addBtn = document.getElementById("addMember");
const modal = document.getElementById("Modal");
const cancelBtn = document.getElementById("closeModal");
let chkSynchronizeAddresses = document.getElementById("chkSynchronizeAddresses");
const _frmFull = document.getElementById("_frmFull");
let Member = document.getElementById("lstMembers");
let Delete = document.getElementById("delete");
let save = document.getElementById("save");
let fName = document.getElementById("firstName");
let lName = document.getElementById("lastName");
let birthDate = document.getElementById("birthDate");
Delete.disabled = Member.value === 1;
addBtn.onclick = function (){
openPopUp();
console.log('function - correct');
}
cancelBtn.onclick = function (){
let closeTrue = confirm("Close form? You've not saved anything.")
if (closeTrue === true) {
closePopUp();
}
}
chkSynchronizeAddresses.onclick = function (){
console.log("Is this working??");
if (chkSynchronizeAddresses.checked){
document.getElementById("txtPostalAddress").setAttribute("readonly", "true");
document.getElementById("txtPostCode").setAttribute("readonly", "true");
document.getElementById("txtPostalState").setAttribute("readonly", "true");
document.getElementById("txtPostalSuburb").setAttribute("readonly", "true");
document.getElementById("txtPostalCountry").setAttribute("readonly", "true");
copyAddressFields();
}
else {
document.getElementById("txtPostalAddress").removeAttribute("readonly");
document.getElementById("txtPostCode").removeAttribute("readonly")
document.getElementById("txtPostalState").removeAttribute("readonly");
document.getElementById("txtPostalSuburb").removeAttribute("readonly");
document.getElementById("txtPostalCountry").removeAttribute("readonly");
}
}
function copyAddressFields () {
if (chkSynchronizeAddresses.checked){
document.getElementById("txtPostalAddress").value = document.getElementById("txtResidentialAddress").value;
document.getElementById("txtPostCode").value = document.getElementById("txtResiPostCode").value;
document.getElementById("txtPostalSuburb").value = document.getElementById("txtResiSuburb").value;
document.getElementById("txtPostalState").value = document.getElementById("txtResiState").value;
document.getElementById("txtPostalCountry").value = document.getElementById("txtResiCountry").value;
}
}
let idCount = 0
save.onclick = function (){
let fNameValue = fName.value
let lNameValue = lName.value
let bDateValue = birthDate.value
let pCountryValue = document.getElementById("txtPostalCountry").value
let pSuburbValue = document.getElementById("txtPostalSuburb").value
let pStateValue = document.getElementById("txtPostalState").value
let pCodeValue = document.getElementById("txtPostCode").value
let pAddressValue = document.getElementById("txtPostalAddress").value
if (fNameValue === ""){
alert("Please enter your first name to proceed");
return false;
}
else
if (lNameValue === "") {
alert("Please enter your last name to proceed");
return false;
} else if (bDateValue === "") {
alert("Please select a DOB to proceed");
return false;
} else if (pCountryValue === "") {
alert("Please enter your country to continue");
return false;
} else if (pSuburbValue === "") {
alert("Please enter your suburb to continue");
return false;
} else if (pCodeValue === "") {
alert("Please enter your postcode to continue");
return false;
} else if (pAddressValue === "") {
alert("Please enter your Address to continue");
return false;
} else if (pStateValue === "") {
alert("Please enter your state to continue");
return false;
} else {
Member.innerHTML +=
`<option value= >${idCount} ${_frmFull.firstName.value} ${_frmFull.lastName.value}<option>`
idCount++
console.log("check - is increase even working????")
}
closePopUp();
return true;
}
function closePopUp() {
modal.style.display="none";
}
function openPopUp() {
modal.style.display = "block";
}
Delete.onclick = function removeOption () {
Member.remove(Member.options);
console.log("is remove being triggered??")
}
if (Member.options.length == ""){
Delete.disabled = true
}
else {
Delete.disabled = false
}
</script>
</body>
`

The reason why the Delete button is not enabling is because the code that is supposed to enable the Delete button is only run once, when the page loads.
Assuming that this is the code that is supposed to enable the button:
if (Member.options.length == 0){ // changed from Member.options.length == ""
Delete.disabled = true
} else {
Delete.disabled = false
}
This code is only run once, when the page loads and the JavaScript code is run. In order to enable the button properly, we need to run this code every time that Member.options.length changes. One way you can do this is place the code snippet above for disabling/enabling the Delete button inside the onclick listener for the save button and to re-check every time a new user is saved. You would have to add this snippet into every place in your code where Member.options.length could change (inside the listener for the delete button as well).
Full updated code:
MemberList
<h1>Member List</h1>
<form method="post" id="_frmFull">
<label for="lstMembers">Member:</label>
<select size="10"
name="lstMembers"
id="lstMembers">
</select>
<button type="button"
id="addMember"
name="Add Member">
Add Member
</button>
<button type="button"
name="Delete Member"
id="delete">
Delete Member</button>
<div id="Modal" class="modal">
<div class="modal-form">
<label for="memTitle">Title:</label>
<input list="memTitles" name="memTitles" id="memTitle">
<datalist id="memTitles">
<option value="Dr">
<option value="Mr">
<option value="Mrs">
<option value="Ms">
</datalist>
<label for="firstName">First Name:</label>
<input type="text" name="firstName" id="firstName" required="required">
<label for="middleName">Middle Name (optional):</label>
<input type="text" name="middleName" id="middleName">
<label for="lastName">Last Name:</label>
<input type="text" name="lastName" id="lastName" required="required">
<br><br>
<label for="Country">Country:</label>
<input list="countries" name="Country" id="Country">
<datalist id="countries">
<option value="Australia">
<option value="United Kingdom">
<option value="America">
<option value="New Zealand">
</datalist>
<label for="Gender">Gender:</label>
<select name="Gender" id="Gender">
<option>Male</option>
<option>Female</option>
<option>Other</option>
</select>
<label for="birthDate">Birthdate:</label>
<input type="date"
id="birthDate"
min="1900-01-01"
max="2022-12-31" required="required">
<br><br>
<div id="resiAddress">
<p>Residential Address:</p>
<br>
<label for="txtResidentialAddress">Address:</label>
<input type="text" required="required" id="txtResidentialAddress" oninput="copyAddressFields();">
<br><br>
<label for="txtResiPostCode">Postcode:</label>
<input type="text" required="required" id="txtResiPostCode">
<br><br>
<label for="txtResiSuburb">Suburb:</label>
<input type="text" required="required" id="txtResiSuburb">
<br><br>
<label for="txtResiCountry" class="country">Country</label>
<input type="text" required="required" id="txtResiCountry">
<br><br>
<label for="txtResiState">State:</label>
<input type="text" required="required" id="txtResiState">
</div>
<br><br>
<label for="chkSynchronizeAddresses">Same as residential </label>
<input type="checkbox" required="required" id="chkSynchronizeAddresses" >
<div id="postAddress">
<p>Postal Address:</p>
<br>
<label for="txtPostalAddress">Address:</label>
<input type="text" id="txtPostalAddress">
<br><br>
<label for="txtPostCode">Postcode:</label>
<input type="text" id="txtPostCode">
<br><br>
<label for="txtPostalSuburb">Suburb:</label>
<input type="text" id="txtPostalSuburb">
<br><br>
<label for="txtPostalCountry">Country:</label>
<input type="text" id="txtPostalCountry">
<br><br>
<label for="txtPostalState">State:</label>
<input type="text" id="txtPostalState">
</div>
<br><br>
<label for="txtPhone" class="phone">Phone: (optional)</label>
<input id="txtPhone" type="text">
<br><br>
<label for="txtMobile" class="mobile">Mobile: (optional)</label>
<input id="txtMobile" type="text">
<br><br>
<button type="button" name="save" id="save">Save</button>
<br><br>
<button type="button"
name="cancel"
id="closeModal">
Cancel</button>
</div>
</div>
</form>
<script>
console.log("Log test - please work!!")
const addBtn = document.getElementById("addMember");
const modal = document.getElementById("Modal");
const cancelBtn = document.getElementById("closeModal");
let chkSynchronizeAddresses = document.getElementById("chkSynchronizeAddresses");
const _frmFull = document.getElementById("_frmFull");
let Member = document.getElementById("lstMembers");
let Delete = document.getElementById("delete");
let save = document.getElementById("save");
let fName = document.getElementById("firstName");
let lName = document.getElementById("lastName");
let birthDate = document.getElementById("birthDate");
Delete.disabled = Member.options.length == 0
addBtn.onclick = function (){
openPopUp();
console.log('function - correct');
}
cancelBtn.onclick = function (){
let closeTrue = confirm("Close form? You've not saved anything.")
if (closeTrue === true) {
closePopUp();
}
}
chkSynchronizeAddresses.onclick = function (){
console.log("Is this working??");
if (chkSynchronizeAddresses.checked){
document.getElementById("txtPostalAddress").setAttribute("readonly", "true");
document.getElementById("txtPostCode").setAttribute("readonly", "true");
document.getElementById("txtPostalState").setAttribute("readonly", "true");
document.getElementById("txtPostalSuburb").setAttribute("readonly", "true");
document.getElementById("txtPostalCountry").setAttribute("readonly", "true");
copyAddressFields();
}
else {
document.getElementById("txtPostalAddress").removeAttribute("readonly");
document.getElementById("txtPostCode").removeAttribute("readonly")
document.getElementById("txtPostalState").removeAttribute("readonly");
document.getElementById("txtPostalSuburb").removeAttribute("readonly");
document.getElementById("txtPostalCountry").removeAttribute("readonly");
}
}
function copyAddressFields () {
if (chkSynchronizeAddresses.checked){
document.getElementById("txtPostalAddress").value = document.getElementById("txtResidentialAddress").value;
document.getElementById("txtPostCode").value = document.getElementById("txtResiPostCode").value;
document.getElementById("txtPostalSuburb").value = document.getElementById("txtResiSuburb").value;
document.getElementById("txtPostalState").value = document.getElementById("txtResiState").value;
document.getElementById("txtPostalCountry").value = document.getElementById("txtResiCountry").value;
}
}
let idCount = 0
save.onclick = function (){
let fNameValue = fName.value
let lNameValue = lName.value
let bDateValue = birthDate.value
let pCountryValue = document.getElementById("txtPostalCountry").value
let pSuburbValue = document.getElementById("txtPostalSuburb").value
let pStateValue = document.getElementById("txtPostalState").value
let pCodeValue = document.getElementById("txtPostCode").value
let pAddressValue = document.getElementById("txtPostalAddress").value
if (fNameValue === ""){
alert("Please enter your first name to proceed");
return false;
}
else
if (lNameValue === "") {
alert("Please enter your last name to proceed");
return false;
} else if (bDateValue === "") {
alert("Please select a DOB to proceed");
return false;
} else if (pCountryValue === "") {
alert("Please enter your country to continue");
return false;
} else if (pSuburbValue === "") {
alert("Please enter your suburb to continue");
return false;
} else if (pCodeValue === "") {
alert("Please enter your postcode to continue");
return false;
} else if (pAddressValue === "") {
alert("Please enter your Address to continue");
return false;
} else if (pStateValue === "") {
alert("Please enter your state to continue");
return false;
} else {
Member.innerHTML +=
`<option value= >${idCount} ${_frmFull.firstName.value} ${_frmFull.lastName.value}<option>`
idCount++
console.log("check - is increase even working????")
if (Member.options.length == 0){
Delete.disabled = true
}
else {
Delete.disabled = false
}
}
closePopUp();
return true;
}
function closePopUp() {
modal.style.display="none";
}
function openPopUp() {
modal.style.display = "block";
}
Delete.onclick = function removeOption () {
Member.remove(Member.options);
if (Member.options.length == 0) {
Delete.disabled = true
}
else {
Delete.disabled = false
}
console.log("is remove being triggered??")
}
</script>
</body>

so if i understood correctly you want to toggle a button if a is populated
In that case you want to keep track of the options
You can use
document.querySelectoAll('options')
and store it in a variable
then write a function that check if there's a value in that variable and disable or enable the button based on that.
Here's a fiddle:
https://jsfiddle.net/skm7bcr6/15/

Disabling jquery submit button until all the form inputs is filled

Disabling jquery submit button until all the form inputs is filled.
Am working with Jquery and I have been trying to implement disabling form submission button until the whole form inputs are filled. i have tried most solution found here but it does not solve the issue. Thanks
$('.postbtn_video').click(function() {
var element = $(this);
var ID = element.attr('id');
var msg = $('#status').val();
var title = $('#title').val();
var video = $('#video').val();
var stat = $('#stat').val();
if (title == "") {
alert('Please Enter video Post Title?');
} else if (msg == "") {
alert('Please Enter Video Post Description');
} else if (video == "") {
alert('Enter Youtube Video Link');
} else if (stat == "") {
alert('Select Status');
} else {
var postData = "post=" + msg + "&title=" + title + "&video=" + video + "&stat=" + stat;
$("#loader").show();
$("#loader").fadeIn(400).html('<img src="loader.gif" align="absmiddle"> <span class="loading">Loading Update...</span>');
$.ajax({
type: "POST",
url: "posts.php",
data: postData,
cache: false,
success: function(html) {
$("ul#updatepost").prepend(html);
$("ul#updatepost li:first").slideDown("slow");
$('#status').val('');
$('#loader').hide();
}
});
}
return false;
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="" method="post" name="statusform">
<label>Video Post Title </label>
<input type="text" name="title" id="title" class="form-control" placeholder="Enter Post Title">
<p></p>
<label>Video Post Description</label>
<textarea style="width:100%" name="status" class="status form-control" id="status" placeholder="Share what you like " title="What's on your mind?">
</textarea>
<label>Youtube Video Link</label>
<input style="width:100%" name="video" class="form-control" id="video" placeholder="Youtube Video Link">
<label>status</label>
<select style="width:100%" name="stat" class="form-control" id="stat">
<option value="ok">ok</option>
</select>
<p></p>
<input name="post" type="submit" value="Share Video Updates" class="postbtn_video" style="background:black;color:white; height:30px;float:left" />
</form>

Firstly apply disabled="disabled" to the button:
<input name="post" type="submit" value="Share Video Updates" class="postbtn_video" disabled="disabled" />
Secondly, you need a function which will check each field is empty or not!
Check below code:
$(document).ready(function(){
$('form > input').keyup(function() {
var empty = false;
$('form > input').each(function() {
if(!empty){ // this will only check next inputs if empty is false, but once its set to true no further check will be made
if ($(this).val() == '') {
empty = true;
}
}
});
if (empty) {
$('.postbtn_video').attr('disabled', 'disabled');
} else {
$('.postbtn_video').removeAttr('disabled');
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="" method="post" name="statusform">
<label>Video Post Title </label>
<input type="text" name="title" id="title" class="form-control" placeholder="Enter Post Title">
<p></p>
<label>Video Post Description</label>
<textarea style="width:100%" name="status" class="status form-control" id="status" placeholder="Share what you like " title="What's on your mind?"></textarea>
<label>Youtube Video Link</label>
<input style="width:100%" name="video" class="form-control" id="video" placeholder="Youtube Video Link">
<label>status</label>
<select style="width:100%" name="stat" class="form-control" id="stat">
<option value="ok">ok</option>
</select>
<p></p>
<input name="post" type="submit" value="Share Video Updates" class="postbtn_video" disabled="disabled" />
</form>

Maybe this will help. you can manipulated the Form Disabled attribute:
var checkboxes = document.getElementsByTagName('input');
//check all check all input elements to see if they are check-boxes
for (var i = 0; i < checkboxes.length; i++) {
//If the input is a check-box run script else skip over
if (checkboxes[i].type == 'checkbox') {
//If it is a check-box ensure the box is unchecked
checkboxes[i].checked = false;
}
}
$(document).ready(function()
{
//define Element by ID and create variable
var $checked = $('#field_human');
//define default state for attribute before handler function trigger
$("#submit").attr("disabled", !$checked.checked)
//On element handler trigger define function to execute each time handler is triggered
$checked.click(function()
{
//State to define instance on method
if ($checked.prop('checked'))
{
//return true
//remove element attribute state 'disabled'
$('#submit').removeAttr('disabled');
}
if($('#contactForm input').val() != '')
{
$('#submit').removeAttr('disabled');
}
else {
//return false
//set element attribute state 'disabled'
$("#submit").attr("disabled", !$checked.checked);
}
//return to ready-state to wait for handler to trigger again
return;
});
});
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<form class="form-horizontal" role="form" method="post" action="" id="contactForm" name="contactForm">
<div class="form-group">
<label for="inputblk" class="col-sm-3 control-label">Input Block</label>
<div class="col-sm-9">
<input name="inputblk" class="form-control" />
</div>
</div>
<div class="form-group">
<label for="human" class="col-sm-3 control-label">Are You <strong><u>Human</u>?</strong></label>
<div class="col-sm-9">
<input id="field_human" class="field_human" type="checkbox" name="human" />
</div>
</div>
<div class="form-group">
<div class="col-sm-9 col-sm-offset-3">
<button id="submit" name="submit" type="submit" class="btn btn-dark btn-block btn-lg">Send</button>
</div>
</div>
</form>

1st:
inputs that you think are required, make it required! like below:
<input style="width:100%" name="video" class="form-control" id="video" placeholder="Youtube Video Link" required >
2nd:
Make your selection based on this attribute and check if values of these inputs are not empty. Disable the submit button if so.
3rd:
Make event listener to all inputs that have required attribute to listen user inputs.
something like this:
var l = $("[required='']");
function enableSubmit(l) {
if (l.length == 0) {
$("[name=post]").removeAttr('disabled');
} else {
for (var m = 0; m < l.length; m++) {
if (l[m].value.length == 0) {
$("[name=post]").attr("disabled", "disabled");
return;
}
}
$("[name=post]").removeAttr('disabled');
}
}
for (var m = 0; m < l.length; m++) {
l[m].addEventListener('input', function () {
enableSubmit(l);
});
}

First of all you need to add a disabled property to you input button by default like:
<input disabled name="post" type="submit" value="Share Video Updates" class="postbtn_video" style="background:black;color:white; height:30px;float:left" />
then in your jquery you need fire up a validate function that will check for all the inputs and if they are not empty you can simply remove the disabled property from your input button like:
$(document).on('keyup', "input:not([type='submit']", function () {
//set it to true by default
var valid = true;
//getting all the inputs except input submit
var inputTextboxes = $("input:not([type='submit'])");
inputTextboxes.each(function(e) {
//it enters this only if the valid is true for any one value, if valid is set to false at any point it won't check it for next inputs - works for first time
if (valid != false){
if ($(this).val()) {
valid = true;
}else{
valid = false;
}
}
else{
break; //breaks the loop
}
});
if (valid) {
$("input[type=submit]").prop("disabled", false);
} else {
$("input[type=submit]").prop("disabled", true);
}
}
Hope this helps

Contact Form Redirecting Prevent Default Not Working

I've tried this many different ways... don't know why this is redirecting still. I suppose in the past I've always used a button instead of a submit input and as such I never ran into this issue. However, I think it's time to get to the bottom of this!
HTML FORM
<form class="col-xs-12" action="mail.php" method="POST" >
<h2 class="headerFont">Contact</h2>
<p>Use the form below to send to contact me via email. I will be in touch soon after receiving your message.</p>
<div class="row">
<div class="col-xs-12 col-sm-6">
<input class="col-xs-12" placeholder="Full Name" title="Enter Full Name" type="text" name="name">
<input class="col-xs-6" placeholder="Email Address" title="Enter Email Address" type="email" name="email">
<input class="col-xs-6" placeholder="Mobile Phone Number" title="Enter Mobile Phone Number" type="tel" name="phone">
<input class="col-xs-12" placeholder="Street Address" title="Enter Street Address" type="text" name="address">
<input type="text" name="_gotcha" id="_gotcha" style="display: none !important">
<select class="col-xs-12" name="service">
<option selected disabled>Select Service</option>
<option>Group Walking</option>
<option>Private Walking</option>
<option>Pet Sitting</option>
</select>
</div>
<div class="col-xs-12 col-sm-6">
<textarea class="col-xs-12" placeholder="Message Here" rows="10" name="message"></textarea>
</div>
</div>
<input type="submit" value="Send" onclick="formSubmit(e)">
</form>
JAVASCRIPT CODE
function formSubmit(e) {
e.preventDefault();
return false;
console.log("Ajax Init");
var form = e.target,
data = new FormData(),
xhr = new XMLHttpRequest();
for (var i = 0, ii = form.length - 1; i < ii; ++i) {
var input = form[i];
data.append(input.name, input.value);
if (input.getAttribute("name") !== "_gotcha") {
if (input.value === "" || input.value === null || input.value === "undefined") {
alert("Please fill out all form fields before submitting");
break;
}
}
}
xhr.open(form.method.toUpperCase(), form.action, true);
if (document.getElementById("_gotcha").value.length == 0){
xhr.send(data);
} else {
break;
}
xhr.onloadend = function () {
// done
for (var i = 0, ii = form.length - 1; i < ii; ++i) {
var input = form[i];
input.value = "";
}
alert("Message Sent - Thank You");
};
};

It seems a better option is to use onsubmit attribute.
function formSubmit(form) {
console.log("Ajax Init");
var data = new FormData(form), // simpler
xhr = new XMLHttpRequest();
for (var i = 0, ii = form.length - 1; i < ii; ++i) {
var input = form[i];
//data.append(input.name, input.value);
if (input.getAttribute("name") !== "_gotcha") {
if (input.value === "" || input.value === null || input.value === "undefined") {
alert("Please fill out all form fields before submitting");
// something went wrong, prevent form from submitting
return false;
}
}
}
xhr.open(form.method.toUpperCase(), form.action, true);
if (document.getElementById("_gotcha").value.length == 0) {
xhr.send(data);
} else {
// something went wrong, prevent form from submitting
return false;
}
xhr.onloadend = function() {
// done
for (var i = 0, ii = form.length - 1; i < ii; ++i) {
var input = form[i];
input.value = "";
}
alert("Message Sent - Thank You");
};
// everything went ok, submit form
return true;
};
<!-- note the use of return -->
<form class="col-xs-12" action="mail.php" method="POST" onsubmit="return formSubmit(this)">
<h2 class="headerFont">Contact</h2>
<p>Use the form below to send to contact me via email. I will be in touch soon after receiving your message.</p>
<div class="row">
<div class="col-xs-12 col-sm-6">
<input class="col-xs-12" placeholder="Full Name" title="Enter Full Name" type="text" name="name">
<input class="col-xs-6" placeholder="Email Address" title="Enter Email Address" type="email" name="email">
<input class="col-xs-6" placeholder="Mobile Phone Number" title="Enter Mobile Phone Number" type="tel" name="phone">
<input class="col-xs-12" placeholder="Street Address" title="Enter Street Address" type="text" name="address">
<input type="text" name="_gotcha" id="_gotcha" style="display: none !important">
<select class="col-xs-12" name="service">
<option selected disabled>Select Service</option>
<option>Group Walking</option>
<option>Private Walking</option>
<option>Pet Sitting</option>
</select>
</div>
<div class="col-xs-12 col-sm-6">
<textarea class="col-xs-12" placeholder="Message Here" rows="10" name="message"></textarea>
</div>
</div>
<!-- upon clicking on the submit button, it will trigger the form's onsubmit handler -->
<input type="submit" value="Send">
</form>

i suggest to use jquery inside of core javascript becuase in javascript it to mush code want to write , i write for you in jquery
step 1: : give id to form tag id="myForm"
step 2: : write script like this
<script>
$('#myForm').submit(function(e){
e.preventDefualt();
data = $(this)..serialize();
});
</script>

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>

Form sent but validation has error

My form is not working well. Although there's error, it's still able to go through. Errflag is 1 but it goes to the '0'. Appreciate if someone can shed some light.
JSFiddle: https://jsfiddle.net/rezasan/xxqtuc7d/
HTML
<form id="contact_form">
<div class="medium-6 columns">
<input type="hidden" name="sourcepage" value="Index Page">
<input type="text" placeholder="NAME" name="name" id="name" required />
<input type="email" placeholder="EMAIL" name="email" id="email" required/>
<input type="text" placeholder="TEL" name="phone" id="phone" required/>
<select name="services" id="serviceslist">
<option value="services" selected>SERVICES</option>
<option value="botox">Botox</option>
<option value="filler">Filler</option>
<option value="Ultherapy">Ultherapy</option>
<option value="coolsculpting">CoolSculpting</option>
<option value="threadlift">Thread Lift</option>
<option value="others">Others</option>
</select>
<div class="errtext"></div>
</div>
<div class="medium-6 columns">
<textarea rows="6" cols="55" name="message" id="message" placeholder="Please enter your enquiries"></textarea>
<input type="submit" style="float:right;" id="submit" name="submit" class="formelement-submit">
</div>
</form>
JAVASCRIPT
function trimStr (str) {
return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
}
function checkTFieldValue(target,value,errorclass) {
if(trimStr($(target).val()) == value) {
$(target).addClass(errorclass);
return 1;
} else{
return 0;
}
}
function checkSFieldValue(target,value,errorclass) {
if(value == "SERVICES") {
$(target).addClass(errorclass);
return 1;
} else{
return 0;
}
}
function checkEmailValue(target,value,errorclass) {
var err = 0;
var emailReg = /^([\w-\.]+#([\w-]+\.)+[\w-]{2,4})?$/;
if(trimStr($(target).val()) == value) {
$(target).addClass(errorclass);
err = 1;
} else if(!emailReg.test($(target).val())) {
$(target).addClass(errorclass);
err = 1;
}
return err;
}
$('#contact_form').append('<input type="hidden" name="jsauth" value="dryga-f"/>');
$('.formelement-submit').click(function(e){
e.preventDefault();
e.stopPropagation();
var errflag = 0;
var counter = 0;
$('.formerror').removeClass('formerror');
$('.errtext').empty();
var e = document.getElementById("serviceslist");
var strUser = e.options[e.selectedIndex].text;
errflag = checkTFieldValue('#name','','formerror');
errflag = checkEmailValue('#email','','formerror');
errflag = checkTFieldValue('#phone','','formerror');
errflag = checkSFieldValue('#serviceslist',strUser,'formerror');
errflag = checkTFieldValue('#message','','formerror');
if(errflag == 1){
$('.errtext').html('<p>*Please fill in all the required fields</p>');
}
if(errflag == 0){
$('.errtext').html('No error');
}
});

if #message is valid then it overwrites all others with 0.
you need to += the errflag and check for >:-
errflag += checkTFieldValue('#name','','formerror');
errflag += checkEmailValue('#email','','formerror');
errflag += checkTFieldValue('#phone','','formerror');
errflag += checkSFieldValue('#serviceslist',strUser,'formerror');
errflag += checkTFieldValue('#message','','formerror');
if(errflag > 0){
$('.errtext').html('<p>*Please fill in all the required fields</p>');
}
else {
$('.errtext').html('No error');
}
also, as #MarcoScabbiolo suggests, use submit instead of click.

When using forms, it's better to attach your validation handler into the form's submit event, not on the click of the submit button. Because there are other ways the form could submit, like pressing enter on an input.
Change
$('.formelement-submit').click(
To
$('#contact_form').on('submit',
It's working in this fiddler