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Don't append if string already contains OnChange

I have a javascript OnChange function on a column having textboxes which captures the name of each row in a column. I am appending all the names and storing in variable.
Now , suppose user clicks same textbox again , I don't want to append that name again.
var AppendedString = null;
function onChangeTest(textbox) {
AppendedString = AppendedString;
AppendedString = AppendedString + ';' + textbox.name;
// this gives null;txt_2_4;txt_2_6;txt_3_4;txt_2_4 and so on..and I don't want to append same name again , here it's txt_2_4
}
My Input text :
<input type="text" name="txt_<%=l_profileid %>_<%=l_processstepsequence%>" value="<%= l_comments%>" onfocus="this.oldvalue = this.value;" onchange="onChangeTest(this);this.oldvalue = this.value;">

Those rows seem to have unique names.
you can simply check if AppendedString already contains that name :
var AppendedString=''
function onChangeTest(textbox) {
if (!AppendedString.includes(textbox.name)) {
AppendedString += ';' + textbox.name;
}
}
Codepen Link
You can’t initialize AppendedString as null otherwise, the includes() method won’t be available
otherwise, you can give each row a unique ID, and store in an array IDs that already have been clicked by the user.
var AppendedString = '';
var clickedRows = [];
function onChangeTest(textbox) {
if (!clickedRows.includes(textbox.id)) {
AppendedString += ';' + textbox.name;
clickedRows.push(textbox.id)
}
}

var arr = [];
$("input[type='text']").on("click", function() {
var nowS = ($(this).attr('name'));
if (!(arr.indexOf(nowS) > -1)) {
arr.push(nowS)
}
console.log(arr)
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="text" id="m1" name="lbl1">
<input type="text" id="m2" name="lbl2">
<input type="text" id="m3" name="lbl3">
Somewhat similar to your need,
var arr = [];
$("input[type='text']").on("click", function() {
var nowS = ($(this).attr('name'));
if (!arr.includes(nowS)) {
arr.push(nowS)
}
console.log(arr)
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="text" id="m1" name="lbl1">
<input type="text" id="m2" name="lbl2">
<input type="text" id="m3" name="lbl3">

You can add flag your textboxes and ignore if it's clicked again. Like using jquery you can do something like this:
function onChangeTest(textbox) {
AppendedString = AppendedString;
if (!textbox.hasClass("clicked")){
AppendedString = AppendedString + ';' + textbox.name;
textbox.AddClass("clicked");
}
}

Automatic array in PHP

How about, make this example, where we put an initial number and final number.
Example We insert the Initial and Final Number:
Initial Number = 1 Final Number = 4
Result = 1 2 3 4
The result is thrown when we press the SEND button.
What I want is that I throw my result without having to press the SEND button.
That the FOR cycle is performed and I throw the result without pressing the button.
That the result is automatic.
CODE:
<form action="" method="post">
<input type="text" name="inivalue" id="inivalue" placeholder="initial value"/>
<input type="text" name="finvalue" id="finvalue" placeholder="final value"/>
<input type="submit" name="submit" vale="submit" />
</form>
<?php
if(isset($_POST['submit']))
{
$num = (int)$_POST['inivalue'];
$numfin = (int)$_POST['finvalue'];
for($num=$num; $num <= $numfin; $num++)
{
echo $num;
}
}
?>

// Get your input elements using getElementById()
const initialValue = document.getElementById("inivalue");
const finalValue = document.getElementById("finvalue");
const result = document.getElementById("result");
let initialVal = "";
let finalVal = "";
// Every time you change the value in your <input> element
// save that value into the initialVal, finalVal variables.
initialValue.addEventListener("change", function(){
initialVal = this.value;
autoArray(initialVal,finalVal);
});
finalValue.addEventListener("change", function(){
finalVal= this.value;
autoArray(initialVal,finalVal);
});
// Loop using initialVal and finalVal
function autoArray(ini,fin){
numArray = [];
if (ini!= "" && fin != "") {
for(i = ini; i <= fin; i++){
numArray.push(i);
}
}
// Change the value of the result <input> element
result.value = numArray;
}
<input type="text" name="inivalue" id="inivalue" placeholder="initial value"/>
<input type="text" name="finvalue" id="finvalue" placeholder="final value"/>
<input type="text" id="result"/>

One way this can be done is using the onChange event.
set it in your final number field:
<input onchange = "rangefinder()" type="text" name="finvalue" id="finvalue" placeholder="final value"/>
then in your javascript function rangefinder():
function rangefinder(){
//get the value of both the invalue and finalvalue fields
//make sure they're both integers - just return if they're not.
//use a for loop to make a string of numbers from invalue to finalvalue
//insert this string where ever you want it.
}
I'll leave the actual JS up to you.

Add to multiple select list with javascript from form

I'd like to have 2 blank input forms - category and value which when a button is pressed and they're appended/added to 2 multiple select forms, category and value. The data isn't being entered when the button is pressed.
function doAdd() {
// Pick up data from the category and value input fields;
// In my form these are named 'cat' and 'val'
var catstr = document.getElementById("cat").value;
var valstr = document.getElementById("val").value;
// pick up references to the text areas;
var cats = document.getElementById("catlist");
var nums = document.getElementById("numlist");
// Append text, inserting a new line character between
// data sets.
if (numadded > 0) {
cats.value = cats.value + "\n";
nums.value = nums.value + "\n";
}
numadded++;
cats.value = cats.value + catstr;
nums.value = nums.value + valstr;
}
HTML important lines
<script type="text/javascript" src="./checksubmit.js" ></script>
<input type="text" id="val" name="val" size="10"/>
<input type="text" id="cat" name="cat" size="30"/>
<input type="button" onclick="doAdd();" value="Add item">
<select multiple="multiple" id="catlist" style="width: 250px;"/>
<select multiple="multiple" id="numlist" style="width: 250px;"/>

I believe you want something like this
Demo fiddle
function doAdd() {
// Pick up data from the category and value input fields;
// In my form these are named 'cat' and 'val'
var catstr = document.getElementById("cat").value;
var valstr = document.getElementById("val").value;
// pick up references to the text areas;
var cats = document.getElementById("catlist");
var nums = document.getElementById("numlist");
//Create and append new options
var catOption = new Option(catstr, valstr);
var numOption = new Option(valstr, valstr);
cats.appendChild(catOption);
nums.appendChild(numOption);
}

why are names not being added to the list?

I found this fiddle and I am trying to get it to work...I can not figure out why the names are not being added to the list, for some reason Add button is acting like a submit button and I can not tell why...It should add all the numbers to a list so when I click submit, then it should send the numbers in an array..
JavaScript:
function bindName() {
var inputNames = document.getElementById("names").getElementsByTagName("inputNames");
for (i = 0; i < inputNames.length; i++) {
inputNames[i].onkeydown = function() {
if (this.value == "") {
setTimeout(deletename(this), 1000);
}
}
}
}
document.getElementById("addName").onclick = function() {
var num1 = document.getElementById("name");
var myRegEx = /^[0-9]{10}$/;
var myRegEx = /^[0-9]{10}$/;
var itemsToTest = num1.value;
if (myRegEx.test(itemsToTest)) {
var form1 = document.getElementById("names");
var nameOfnames = form1.getElementsByTagName("inputNames").length;
var newGuy1 = document.createElement("inputNames");
newGuy1.setAttribute("id", nameOfnames);
newGuy1.setAttribute("type", "text");
newGuy1.setAttribute("value", num1.value);
form1.appendChild(newGuy1);
num1.value = "";
bindName();
}
else {
alert('error');
}
};
HTML:
<h1>Enter Name</h1>
<div id="mainName">
<h2>name</h2>
<label for="name">Add Names: </label>
<input id="name" type="text">
<button id="addName">Add</button>
<form>
<div id="names">
</div>
<input METHOD="POST" action="text.php" type="submit" value="Submit">
</form>
</div>

I've seen
document.createElement("inputNames");
Shouldn't be
document.createElement("input");
?

Because this /^[0-9]{10}$/; will accept only 10 numbers and only that, try entering 1234567890 and you will see no error.

I'm not sure why your "name" field is restricted to 10 digit numbers, but I've got the thing to work.
http://jsfiddle.net/y8Uju/4/
I think the problem was that you were trying to create an element with the tag name inputNames, but that's not a valid tag. Instead I changed it to create inputs, and set the class to inputNames.

How can I get form data with JavaScript/jQuery?

Is there a simple, one-line way to get the data of a form as it would be if it was to be submitted in the classic HTML-only way?
For example:
<form>
<input type="radio" name="foo" value="1" checked="checked" />
<input type="radio" name="foo" value="0" />
<input name="bar" value="xxx" />
<select name="this">
<option value="hi" selected="selected">Hi</option>
<option value="ho">Ho</option>
</form>
Output:
{
"foo": "1",
"bar": "xxx",
"this": "hi"
}
Something like this is too simple, since it does not (correctly) include textareas, selects, radio buttons and checkboxes:
$("#form input").each(function () {
data[theFieldName] = theFieldValue;
});

Use $('form').serializeArray(), which returns an array:
[
{"name":"foo","value":"1"},
{"name":"bar","value":"xxx"},
{"name":"this","value":"hi"}
]
Other option is $('form').serialize(), which returns a string:
"foo=1&bar=xxx&this=hi"
Take a look at this jsfiddle demo

$('form').serialize() //this produces: "foo=1&bar=xxx&this=hi"
demo

Updated answer for 2014: HTML5 FormData does this
var formData = new FormData(document.querySelector('form'))
You can then post formData exactly as it is - it contains all names and values used in the form.

Based on jQuery.serializeArray, returns key-value pairs.
var data = $('#form').serializeArray().reduce(function(obj, item) {
obj[item.name] = item.value;
return obj;
}, {});

document.querySelector('form').addEventListener('submit', (e) => {
const formData = new FormData(e.target);
// Now you can use formData.get('foo'), for example.
// Don't forget e.preventDefault() if you want to stop normal form .submission
});
This is a nitpicky answer, but let me explain why this is a better solution:
We're properly handling a form submit rather than a button press. Some people like to push enter on fields. Some people use alternative input devices such as speech input or other accessibility devices. Handle the form submit and you correctly solve it for everyone.
We're digging into the form data for the actual form that was submitted. If you change your form selector later, you don't have to change the selectors for all the fields. Furthermore, you might have several forms with the same input names. No need to disambiguate with excessive IDs and what not, just track the inputs based on the form that was submitted. This also enables you to use a single event handler for multiple forms if that is appropriate for your situation.
The FormData interface is fairly new, but is well supported by browsers. It's a great way to build that data collection to get the real values of what's in the form. Without it, you're going to have to loop through all the elements (such as with form.elements) and figure out what's checked, what isn't, what the values are, etc. Totally possible if you need old browser support, but the FormData interface is simpler.
I'm using ES6 here... not a requirement by any means, so change it back to be ES5 compatible if you need old browser support.

It is 2019 and there's a better way to do this:
const form = document.querySelector('form');
const data = new URLSearchParams(new FormData(form).entries());
or if you want a plain Object instead
const form = document.querySelector('form');
const data = Object.fromEntries(new FormData(form).entries());
although note that this won't work with duplicate keys like you get from multi-select and duplicate checkboxes with the same name.

Simplest way, 2022.
document.querySelector('form').addEventListener('submit', (e) => {
const data = Object.fromEntries(new FormData(e.target).entries());
console.log(data)
});
Output
{ name: 'Stackoverflow' }

use .serializeArray() to get the data in array format and then convert it into an object:
function getFormObj(formId) {
var formObj = {};
var inputs = $('#'+formId).serializeArray();
$.each(inputs, function (i, input) {
formObj[input.name] = input.value;
});
return formObj;
}

Here's a really simple and short soluton that even doesn't require Jquery.
var formElements=document.getElementById("myForm").elements;
var postData={};
for (var i=0; i<formElements.length; i++)
if (formElements[i].type!="submit")//we dont want to include the submit-buttom
postData[formElements[i].name]=formElements[i].value;

I use this:
jQuery Plugin
(function($){
$.fn.getFormData = function(){
var data = {};
var dataArray = $(this).serializeArray();
for(var i=0;i<dataArray.length;i++){
data[dataArray[i].name] = dataArray[i].value;
}
return data;
}
})(jQuery);
HTML Form
<form id='myform'>
<input name='myVar1' />
<input name='myVar2' />
</form>
Get the Data
var myData = $("#myForm").getFormData();

$("#form input, #form select, #form textarea").each(function() {
data[theFieldName] = theFieldValue;
});
other than that, you might want to look at serialize();

Here is a working JavaScript only implementation which correctly handles checkboxes, radio buttons, and sliders (probably other input types as well, but I've only tested these).
function setOrPush(target, val) {
var result = val;
if (target) {
result = [target];
result.push(val);
}
return result;
}
function getFormResults(formElement) {
var formElements = formElement.elements;
var formParams = {};
var i = 0;
var elem = null;
for (i = 0; i < formElements.length; i += 1) {
elem = formElements[i];
switch (elem.type) {
case 'submit':
break;
case 'radio':
if (elem.checked) {
formParams[elem.name] = elem.value;
}
break;
case 'checkbox':
if (elem.checked) {
formParams[elem.name] = setOrPush(formParams[elem.name], elem.value);
}
break;
default:
formParams[elem.name] = setOrPush(formParams[elem.name], elem.value);
}
}
return formParams;
}
Working example:
function setOrPush(target, val) {
var result = val;
if (target) {
result = [target];
result.push(val);
}
return result;
}
function getFormResults(formElement) {
var formElements = formElement.elements;
var formParams = {};
var i = 0;
var elem = null;
for (i = 0; i < formElements.length; i += 1) {
elem = formElements[i];
switch (elem.type) {
case 'submit':
break;
case 'radio':
if (elem.checked) {
formParams[elem.name] = elem.value;
}
break;
case 'checkbox':
if (elem.checked) {
formParams[elem.name] = setOrPush(formParams[elem.name], elem.value);
}
break;
default:
formParams[elem.name] = setOrPush(formParams[elem.name], elem.value);
}
}
return formParams;
}
//
// Boilerplate for running the snippet/form
//
function ok() {
var params = getFormResults(document.getElementById('main_form'));
document.getElementById('results_wrapper').innerHTML = JSON.stringify(params, null, ' ');
}
(function() {
var main_form = document.getElementById('main_form');
main_form.addEventListener('submit', function(event) {
event.preventDefault();
ok();
}, false);
})();
<form id="main_form">
<div id="questions_wrapper">
<p>what is a?</p>
<div>
<input type="radio" required="" name="q_0" value="a" id="a_0">
<label for="a_0">a</label>
<input type="radio" required="" name="q_0" value="b" id="a_1">
<label for="a_1">b</label>
<input type="radio" required="" name="q_0" value="c" id="a_2">
<label for="a_2">c</label>
<input type="radio" required="" name="q_0" value="d" id="a_3">
<label for="a_3">d</label>
</div>
<div class="question range">
<label for="a_13">A?</label>
<input type="range" required="" name="q_3" id="a_13" min="0" max="10" step="1" list="q_3_dl">
<datalist id="q_3_dl">
<option value="0"></option>
<option value="1"></option>
<option value="2"></option>
<option value="3"></option>
<option value="4"></option>
<option value="5"></option>
<option value="6"></option>
<option value="7"></option>
<option value="8"></option>
<option value="9"></option>
<option value="10"></option>
</datalist>
</div>
<p>A and/or B?</p>
<div>
<input type="checkbox" name="q_4" value="A" id="a_14">
<label for="a_14">A</label>
<input type="checkbox" name="q_4" value="B" id="a_15">
<label for="a_15">B</label>
</div>
</div>
<button id="btn" type="submit">OK</button>
</form>
<div id="results_wrapper"></div>
edit:
If you're looking for a more complete implementation, then take a look at this section of the project I made this for. I'll update this question eventually with the complete solution I came up with, but maybe this will be helpful to someone.

I have included the answer to also give back the object required.
function getFormData(form) {
var rawJson = form.serializeArray();
var model = {};
$.map(rawJson, function (n, i) {
model[n['name']] = n['value'];
});
return model;
}

Based on neuront's response I created a simple JQuery method that gets the form data in key-value pairs but it works for multi-selects and for array inputs with name='example[]'.
This is how it is used:
var form_data = $("#form").getFormObject();
You can find an example below of its definition and how it works.
// Function start
$.fn.getFormObject = function() {
var object = $(this).serializeArray().reduce(function(obj, item) {
var name = item.name.replace("[]", "");
if ( typeof obj[name] !== "undefined" ) {
if ( !Array.isArray(obj[name]) ) {
obj[name] = [ obj[name], item.value ];
} else {
obj[name].push(item.value);
}
} else {
obj[name] = item.value;
}
return obj;
}, {});
return object;
}
// Function ends
// This is how it's used
$("#getObject").click( function() {
var form_data = $("#form").getFormObject();
console.log(form_data);
});
/* Only to make view better ;) */
#getObject {
padding: 10px;
cursor:pointer;
background:#0098EE;
color:white;
display:inline-block;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<form id="form">
<input type="text" name="text" value="Hola amigo" />
<input type="text" name="text_array[]" value="Array 1" />
<input type="text" name="text_array[]" value="Array 2" />
<input type="text" name="text_array[]" value="Array 3" />
<select name="multiselect" multiple>
<option name="option1" selected> option 1 </option>
<option name="option2" selected> option 2 </option>
</select>
<input type="checkbox" name="checkbox" value="checkbox1" checked/>
<input type="checkbox" name="checkbox" value="checkbox2" checked/>
<input type="radio" name="radio" value="radio1" checked/>
<input type="radio" name="radio" value="radio2"/>
</form>
<div id="getObject"> Get object (check the console!) </div>

If you are using jQuery, here is a little function that will do what you are looking for.
First, add an ID to your form (unless it is the only form on the page, then you can just use 'form' as the dom query)
<form id="some-form">
<input type="radio" name="foo" value="1" checked="checked" />
<input type="radio" name="foo" value="0" />
<input name="bar" value="xxx" />
<select name="this">
<option value="hi" selected="selected">Hi</option>
<option value="ho">Ho</option>
</form>
<script>
//read in a form's data and convert it to a key:value object
function getFormData(dom_query){
var out = {};
var s_data = $(dom_query).serializeArray();
//transform into simple data/value object
for(var i = 0; i<s_data.length; i++){
var record = s_data[i];
out[record.name] = record.value;
}
return out;
}
console.log(getFormData('#some-form'));
</script>
The output would look like:
{
"foo": "1",
"bar": "xxx",
"this": "hi"
}

You can also use the FormData Objects; The FormData object lets you compile a set of key/value pairs to send using XMLHttpRequest. Its primarily intended for use in sending form data, but can be used independently from forms in order to transmit keyed data.
var formElement = document.getElementById("myform_id");
var formData = new FormData(formElement);
console.log(formData);

This will append all form fields to the JavaScript object "res":
var res = {};
$("#form input, #form select, #form textarea").each(function(i, obj) {
res[obj.name] = $(obj).val();
})

var formData = new FormData($('#form-id'));
params = $('#form-id').serializeArray();
$.each(params, function(i, val) {
formData.append(val.name, val.value);
});

For those of you who would prefer an Object as opposed to a serialized string (like the one returned by $(form).serialize(), and a slight improvement on $(form).serializeArray()), feel free to use the code below:
var Form = {
_form: null,
_validate: function(){
if(!this._form || this._form.tagName.toLowerCase() !== "form") return false;
if(!this._form.elements.length) return false;
return true;
}, _loopFields: function(callback){
var elements = this._form.elements;
for(var i = 0; i < elements.length; i++){
var element = form.elements[i];
if(name !== ""){
callback(this._valueOfField(element));
}
}
}, _valueOfField: function(element){
var type = element.type;
var name = element.name.trim();
var nodeName = element.nodeName.toLowerCase();
switch(nodeName){
case "input":
if(type === "radio" || type === "checkbox"){
if(element.checked){
return element.value;
}
}
return element.value;
break;
case "select":
if(type === "select-multiple"){
for(var i = 0; i < element.options.length; i++){
if(options[i].selected){
return element.value;
}
}
}
return element.value;
break;
case "button":
switch(type){
case "reset":
case "submit":
case "button":
return element.value;
break;
}
break;
}
}, serialize: function(form){
var data = {};
this._form = form;
if(this._validate()){
this._loopFields(function(value){
if(value !== null) data[name] = value;
});
}
return data;
}
};
To execute it, just use Form.serialize(form) and the function will return an Object similar to this:
<!-- { username: "username", password: "password" } !-->
<input type="text" value="username">
<input type="password" value="password">
As a bonus, it means you don't have to install the entire bundle of jQuery just for one serialize function.

I'm kind of supprised because no one mentioned below solution.
Get form data via document.forms.namedItem function
var form = document.forms.namedItem("fileinfo");
form.addEventListener('submit', function(ev) {
var oData = new FormData(form);
}
The HT
<form name="fileinfo">
<label>Your email address:</label>
<input type="email" autocomplete="on" autofocus name="userid" placeholder="email" required size="32" maxlength="64" /><br />
<label>Custom file label:</label>
<input type="text" name="filelabel" size="12" maxlength="32" /><br />
<label>File to stash:</label>
<input type="file" name="file" required />
<input type="submit" value="Stash the file!" />
</form>
<div></div>

I wrote a library to solve this very problem: JSONForms. It takes a form, goes through each input and builds a JSON object you can easily read.
Say you have the following form:
<form enctype='application/json'>
<input name='places[0][city]' value='New York City'>
<input type='number' name='places[0][population]' value='8175133'>
<input name='places[1][city]' value='Los Angeles'>
<input type='number' name='places[1][population]' value='3792621'>
<input name='places[2][city]' value='Chicago'>
<input type='number' name='places[2][population]' value='2695598'>
</form>
Passing the form to JSONForms' encode method returns you the following object:
{
"places": [
{
"city": "New York City",
"population": 8175133
},
{
"city": "Los Angeles",
"population": 3792621
},
{
"city": "Chicago",
"population": 2695598
}
]
}
Here's demo with your form.

function getFormData($form){
var unindexed_array = $form.serializeArray();
var indexed_array = {};
$.map(unindexed_array, function(n, i){
if(indexed_array[n['name']] == undefined){
indexed_array[n['name']] = [n['value']];
}else{
indexed_array[n['name']].push(n['value']);
}
});
return indexed_array;
}

you can use this function for have an object or a JSON from form.
for use it:
var object = formService.getObjectFormFields("#idform");
function getObjectFormFields(formSelector)
{
/// <summary>Função que retorna objeto com base nas propriedades name dos elementos do formulário.</summary>
/// <param name="formSelector" type="String">Seletor do formulário</param>
var form = $(formSelector);
var result = {};
var arrayAuxiliar = [];
form.find(":input:text").each(function (index, element)
{
var name = $(element).attr('name');
var value = $(element).val();
result[name] = value;
});
form.find(":input[type=hidden]").each(function (index, element)
{
var name = $(element).attr('name');
var value = $(element).val();
result[name] = value;
});
form.find(":input:checked").each(function (index, element)
{
var name;
var value;
if ($(this).attr("type") == "radio")
{
name = $(element).attr('name');
value = $(element).val();
result[name] = value;
}
else if ($(this).attr("type") == "checkbox")
{
name = $(element).attr('name');
value = $(element).val();
if (result[name])
{
if (Array.isArray(result[name]))
{
result[name].push(value);
} else
{
var aux = result[name];
result[name] = [];
result[name].push(aux);
result[name].push(value);
}
} else
{
result[name] = [];
result[name].push(value);
}
}
});
form.find("select option:selected").each(function (index, element)
{
var name = $(element).parent().attr('name');
var value = $(element).val();
result[name] = value;
});
arrayAuxiliar = [];
form.find("checkbox:checked").each(function (index, element)
{
var name = $(element).attr('name');
var value = $(element).val();
result[name] = arrayAuxiliar.push(value);
});
form.find("textarea").each(function (index, element)
{
var name = $(element).attr('name');
var value = $(element).val();
result[name] = value;
});
return result;
}

$( "form" ).bind( "submit", function(e) {
e.preventDefault();
console.log( $(this).serializeObject() );
//console.log( $(this).serialize() );
//console.log( $(this).serializeArray() );
});
$.fn.serializeObject = function() {
var o = {};
var a = this.serializeArray();
$.each( a, function() {
if ( o[this.name] !== undefined)
{
if ( ! o[this.name].push )
{
o[this.name] = [o[this.name]];
}
o[this.name].push(this.value || '');
}
else
{
o[this.name] = this.value || '';
}
});
return o;
};
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<form>
<input type="radio" name="foo" value="1" checked="checked" />
<input type="radio" name="foo" value="0" />
<input name="bar" value="xxx" />
<select name="this">
<option value="hi" selected="selected">Hi</option>
<option value="ho">Ho</option>
</select>
<input type="submit" value="Submit" />
</form>
Codepen

I wrote a function that takes care of multiple checkboxes and multiple selects. In those cases it returns an array.
function getFormData(formId) {
return $('#' + formId).serializeArray().reduce(function (obj, item) {
var name = item.name,
value = item.value;
if (obj.hasOwnProperty(name)) {
if (typeof obj[name] == "string") {
obj[name] = [obj[name]];
obj[name].push(value);
} else {
obj[name].push(value);
}
} else {
obj[name] = value;
}
return obj;
}, {});
}

Here is a nice vanilla JS function I wrote to extract form data as an object. It also has options for inserting additions into the object, and for clearing the form input fields.
const extractFormData = ({ form, clear, add }) => {
return [].slice.call(form.children).filter(node => node.nodeName === 'INPUT')
.reduce((formData, input) => {
const value = input.value
if (clear) { input.value = '' }
return {
...formData,
[input.name]: value
}
}, add)
}
Here is an example of its use with a post request:
submitGrudge(e) {
e.preventDefault()
const form = e.target
const add = { id: Date.now(), forgiven: false }
const grudge = extractFormData({ form, add, clear: true })
// grudge = {
// "name": "Example name",
// "offense": "Example string",
// "date": "2017-02-16",
// "id": 1487877281983,
// "forgiven": false
// }
fetch('http://localhost:3001/api/grudge', {
method: 'post',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(grudge)
})
.then(response => response.json())
.then(grudges => this.setState({ grudges }))
.catch(err => console.log('error: ', err))
}

showing form input element fields and input file to submit your form without page refresh and grab all values with file include in it here it is
<form id="imageUploadForm" action="" method="post" enctype="multipart/form-data">
<input type="text" class="form-control" id="fname" name='fname' placeholder="First Name" >
<input type="text" class="form-control" name='lname' id="lname" placeholder="Last Name">
<input type="number" name='phoneno' class="form-control" id="phoneno" placeholder="Phone Number">
<textarea class="form-control" name='address' id="address" rows="5" cols="5" placeholder="Your Address"></textarea>
<input type="file" name="file" id="file" >
<input type="submit" id="sub" value="Registration">
</form>
on Submit button page will send ajax request to your php file.
$('#imageUploadForm').on('submit',(function(e)
{
fname = $('#fname').val();
lname = $('#lname').val();
address = $('#address').val();
phoneno = $('#phoneno').val();
file = $('#file').val();
e.preventDefault();
var formData = new FormData(this);
formData.append('file', $('#file')[0]);
formData.append('fname',$('#fname').val());
formData.append('lname',$('#lname').val());
formData.append('phoneno',$('#phoneno').val());
formData.append('address',$('#address').val());
$.ajax({
type:'POST',
url: "test.php",
//url: '<?php echo base_url().'edit_profile/edit_profile2';?>',
data:formData,
cache:false,
contentType: false,
processData: false,
success:function(data)
{
alert('Data with file are submitted !');
}
});
}))

$(form).serializeArray().reduce(function (obj, item) {
if (obj[item.name]) {
if ($.isArray(obj[item.name])) {
obj[item.name].push(item.value);
} else {
var previousValue = obj[item.name];
obj[item.name] = [previousValue, item.value];
}
} else {
obj[item.name] = item.value;
}
return obj;
}, {});
It will fix issue:couldn't work with multiselects.

Here's my version in vanilla JS (tested on Chrome)
works with:
name="input"
name="form[name]" (creates an object)
name="checkbox[]" (creates an object with an array)
name="form[checkbox][]" (creates an array)
name="form[select][name]" (creates an object with an object containing only the selected value)
/**
* Get the values from a form
* #param formId ( ID without the # )
* #returns {object}
*/
function getFormValues( formId )
{
let postData = {};
let form = document.forms[formId];
let formData = new FormData( form );
for ( const value of formData.entries() )
{
let container = postData;
let key = value[0];
let arrayKeys = key.match( /\[[\w\-]*\]/g ); // Check for any arrays
if ( arrayKeys !== null )
{
arrayKeys.unshift( key.substr( 0, key.search( /\[/ ) ) ); // prepend the first key to the list
for ( let i = 0, count = arrayKeys.length, lastRun = count - 1; i < count; i++ )
{
let _key = arrayKeys[i];
_key = _key.replace( "[", '' ).replace( "]", '' ); // Remove the brackets []
if ( _key === '' )
{
if ( ! Array.isArray( container ) )
{
container = [];
}
_key = container.length;
}
if ( ! (_key in container) ) // Create an object for the key if it doesn't exist
{
if ( i !== lastRun && arrayKeys[i + 1] === '[]' )
{
container[_key] = [];
}
else
{
container[_key] = {};
}
}
if ( i !== lastRun ) // Until we're the last item, swap container with it's child
{
container = container[_key];
}
key = _key;
}
}
container[key] = value[1]; // finally assign the value
}
return postData;
}

You are all not fully correct. You cannot write:
formObj[input.name] = input.value;
Because this way if you have multiselect list - its values will be overwritten with the last one, since it's transmitted as: "param1" : "value1", "param1" : "value2".
So, correct approach is:
if (formData[input.name] === undefined) {
formData[input.name] = input.value;
}
else {
var inputFieldArray = $.merge([], $.isArray(formData[input.name]) ? formData[input.name] : [formData[input.name]]);
$.merge(inputFieldArray, [input.value]);
formData[input.name] = $.merge([], inputFieldArray);
}