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How to get the value field of HTML Control in Javascript?

How to get the value field of HTML Control in Javascript?
Instead of picking the Id , I am trying to get the value which is 4875.
<input data-val="true" data-val-required="Required" id="ChangesInTreatYes" name="ChangesInTreat" type="radio" value="4875" /> Yes
<input id="ChangesInTreatNo" name="ChangesInTreat" type="radio" value="4876" /> No
if ($("input:radio[name='ChangesInTreat']:checked").length > 0) {
var isChecked1 = document.getElementById("ChangesInTreatYes").checked;
alert(isChecked1);
}

jQuery makes it simple -- for nearly all form elements, .val() will return the value of the element.
let toggleEl = $("input[name='ChangesInTreat']")
toggleEl.on("change", function(){
console.log($(this).val() );
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input data-val="true" data-val-required="Required" id="ChangesInTreatYes" name="ChangesInTreat" type="radio" value="4875" /> Yes
<input id="ChangesInTreatNo" name="ChangesInTreat" type="radio" value="4876" /> No
To do the same thing with plain old javascript:
let toggleEl = document.querySelectorAll("input[name='ChangesInTreat']")
// Go over each radio button, and add an event handler
toggleEl.forEach(function(element){
element.addEventListener("change", function(){
console.log(this.value)
})
})
<input data-val="true" data-val-required="Required" id="ChangesInTreatYes" name="ChangesInTreat" type="radio" value="4875" /> Yes
<input id="ChangesInTreatNo" name="ChangesInTreat" type="radio" value="4876" /> No

FYI, you are intermixing jQuery and javascript. Would suggest choosing one type and sticking with it.
Get value of radio using javascript by name:
var isChecked1 = document.querySelector("input[name='ChangesInTreat']:checked").value;
Get value of radio using jQuery by name:
var isChecked1 = $("input[name='ChangesInTreat']:checked").val();

Problems with checkbox required php-js [duplicate]

When using the newer browsers that support HTML5 (FireFox 4 for example);
and a form field has the attribute required='required';
and the form field is empty/blank;
and the submit button is clicked;
the browsers detects that the "required" field is empty and does not submit the form; instead browser shows a hint asking the user to type text into the field.
Now, instead of a single text field, I have a group of checkboxes, out of which at least one should be checked/selected by the user.
How can I use the HTML5 required attribute on this group of checkboxes?
(Since only one of the checkboxes needs to be checked, I can't put the required attribute on each and every checkbox)
ps. I am using simple_form, if that matters.
UPDATE
Could the HTML 5 multiple attribute be helpful here? Has anyone use it before for doing something similar to my question?
UPDATE
It appears that this feature is not supported by the HTML5 spec: ISSUE-111: What does input.#required mean for #type = checkbox?
(Issue status: Issue has been marked closed without prejudice.)
And here is the explanation.
UPDATE 2
It's an old question, but wanted to clarify that the original intent of the question was to be able to do the above without using Javascript - i.e. using a HTML5 way of doing it. In retrospect, I should've made the "without Javascript" more obvious.

Unfortunately HTML5 does not provide an out-of-the-box way to do that.
However, using jQuery, you can easily control if a checkbox group has at least one checked element.
Consider the following DOM snippet:
<div class="checkbox-group required">
<input type="checkbox" name="checkbox_name[]">
<input type="checkbox" name="checkbox_name[]">
<input type="checkbox" name="checkbox_name[]">
<input type="checkbox" name="checkbox_name[]">
</div>
You can use this expression:
$('div.checkbox-group.required :checkbox:checked').length > 0
which returns true if at least one element is checked.
Based on that, you can implement your validation check.

Its a simple trick. This is jQuery code that can exploit the html5 validation by changing the required properties if any one is checked. Following is your html code (make sure that you add required for all the elements in the group.)
<input type="checkbox" name="option[]" id="option-1" value="option1" required/> Option 1
<input type="checkbox" name="option[]" id="option-2" value="option2" required/> Option 2
<input type="checkbox" name="option[]" id="option-3" value="option3" required/> Option 3
<input type="checkbox" name="option[]" id="option-4" value="option4" required/> Option 4
<input type="checkbox" name="option[]" id="option-5" value="option5" required/> Option 5
Following is jQuery script, which disables further validation check if any one is selected. Select using name element.
$cbx_group = $("input:checkbox[name='option[]']");
$cbx_group = $("input:checkbox[id^='option-']"); // name is not always helpful ;)
$cbx_group.prop('required', true);
if($cbx_group.is(":checked")){
$cbx_group.prop('required', false);
}
Small gotcha here: Since you are using html5 validation, make sure you execute this before the it gets validated i.e. before form submit.
// but this might not work as expected
$('form').submit(function(){
// code goes here
});
// So, better USE THIS INSTEAD:
$('button[type="submit"]').on('click', function() {
// skipping validation part mentioned above
});

HTML5 does not directly support requiring only one/at least one checkbox be checked in a checkbox group. Here is my solution using Javascript:
HTML
<input class='acb' type='checkbox' name='acheckbox[]' value='1' onclick='deRequire("acb")' required> One
<input class='acb' type='checkbox' name='acheckbox[]' value='2' onclick='deRequire("acb")' required> Two
JAVASCRIPT
function deRequireCb(elClass) {
el = document.getElementsByClassName(elClass);
var atLeastOneChecked = false; //at least one cb is checked
for (i = 0; i < el.length; i++) {
if (el[i].checked === true) {
atLeastOneChecked = true;
}
}
if (atLeastOneChecked === true) {
for (i = 0; i < el.length; i++) {
el[i].required = false;
}
} else {
for (i = 0; i < el.length; i++) {
el[i].required = true;
}
}
}
The javascript will ensure at least one checkbox is checked, then de-require the entire checkbox group. If the one checkbox that is checked becomes un-checked, then it will require all checkboxes, again!

I guess there's no standard HTML5 way to do this, but if you don't mind using a jQuery library, I've been able to achieve a "checkbox group" validation using webshims' "group-required" validation feature:
The docs for group-required say:
If a checkbox has the class 'group-required' at least one of the
checkboxes with the same name inside the form/document has to be
checked.
And here's an example of how you would use it:
<input name="checkbox-group" type="checkbox" class="group-required" id="checkbox-group-id" />
<input name="checkbox-group" type="checkbox" />
<input name="checkbox-group" type="checkbox" />
<input name="checkbox-group" type="checkbox" />
<input name="checkbox-group" type="checkbox" />
I mostly use webshims to polyfill HTML5 features, but it also has some great optional extensions like this one.
It even allows you to write your own custom validity rules. For example, I needed to create a checkbox group that wasn't based on the input's name, so I wrote my own validity rule for that...

we can do this easily with html5 also, just need to add some jquery code
Demo
HTML
<form>
<div class="form-group options">
<input type="checkbox" name="type[]" value="A" required /> A
<input type="checkbox" name="type[]" value="B" required /> B
<input type="checkbox" name="type[]" value="C" required /> C
<input type="submit">
</div>
</form>
Jquery
$(function(){
var requiredCheckboxes = $('.options :checkbox[required]');
requiredCheckboxes.change(function(){
if(requiredCheckboxes.is(':checked')) {
requiredCheckboxes.removeAttr('required');
} else {
requiredCheckboxes.attr('required', 'required');
}
});
});

Inspired by the answers from #thegauraw and #Brian Woodward, here's a bit I pulled together for JQuery users, including a custom validation error message:
$cbx_group = $("input:checkbox[name^='group']");
$cbx_group.on("click", function () {
if ($cbx_group.is(":checked")) {
// checkboxes become unrequired as long as one is checked
$cbx_group.prop("required", false).each(function () {
this.setCustomValidity("");
});
} else {
// require checkboxes and set custom validation error message
$cbx_group.prop("required", true).each(function () {
this.setCustomValidity("Please select at least one checkbox.");
});
}
});
Note that my form has some checkboxes checked by default.
Maybe some of you JavaScript/JQuery wizards could tighten that up even more?

I added an invisible radio to a group of checkboxes.
When at least one option is checked, the radio is also set to check.
When all options are canceled, the radio is also set to cancel.
Therefore, the form uses the radio prompt "Please check at least one option"
You can't use display: none because radio can't be focused.
I make the radio size equal to the entire checkboxes size, so it's more obvious when prompted.
HTML
<form>
<div class="checkboxs-wrapper">
<input id="radio-for-checkboxes" type="radio" name="radio-for-required-checkboxes" required/>
<input type="checkbox" name="option[]" value="option1"/>
<input type="checkbox" name="option[]" value="option2"/>
<input type="checkbox" name="option[]" value="option3"/>
</div>
<input type="submit" value="submit"/>
</form>
Javascript
var inputs = document.querySelectorAll('[name="option[]"]')
var radioForCheckboxes = document.getElementById('radio-for-checkboxes')
function checkCheckboxes () {
var isAtLeastOneServiceSelected = false;
for(var i = inputs.length-1; i >= 0; --i) {
if (inputs[i].checked) isAtLeastOneCheckboxSelected = true;
}
radioForCheckboxes.checked = isAtLeastOneCheckboxSelected
}
for(var i = inputs.length-1; i >= 0; --i) {
inputs[i].addEventListener('change', checkCheckboxes)
}
CSS
.checkboxs-wrapper {
position: relative;
}
.checkboxs-wrapper input[name="radio-for-required-checkboxes"] {
position: absolute;
margin: 0;
top: 0;
left: 0;
width: 100%;
height: 100%;
-webkit-appearance: none;
pointer-events: none;
border: none;
background: none;
}
https://jsfiddle.net/codus/q6ngpjyc/9/

I had the same problem and I my solution was this:
HTML:
<form id="processForm.php" action="post">
<div class="input check_boxes required wish_payment_type">
<div class="wish_payment_type">
<span class="checkbox payment-radio">
<label for="wish_payment_type_1">
<input class="check_boxes required" id="wish_payment_type_1" name="wish[payment_type][]" type="checkbox" value="1">Foo
</label>
</span>
<span class="checkbox payment-radio">
<label for="wish_payment_type_2">
<input class="check_boxes required" id="wish_payment_type_2" name="wish[payment_type][]" type="checkbox" value="2">Bar
</label>
</span>
<span class="checkbox payment-radio">
<label for="wish_payment_type_3">
<input class="check_boxes required" id="wish_payment_type_3" name="wish[payment_type][]" type="checkbox" value="3">Buzz
</label>
<input id='submit' type="submit" value="Submit">
</div>
</form>
JS:
var verifyPaymentType = function () {
var checkboxes = $('.wish_payment_type .checkbox');
var inputs = checkboxes.find('input');
var first = inputs.first()[0];
inputs.on('change', function () {
this.setCustomValidity('');
});
first.setCustomValidity(checkboxes.find('input:checked').length === 0 ? 'Choose one' : '');
}
$('#submit').click(verifyPaymentType);
https://jsfiddle.net/oywLo5z4/

You don't need jQuery for this. Here's a vanilla JS proof of concept using an event listener on a parent container (checkbox-group-required) of the checkboxes, the checkbox element's .checked property and Array#some.
const validate = el => {
const checkboxes = el.querySelectorAll('input[type="checkbox"]');
return [...checkboxes].some(e => e.checked);
};
const formEl = document.querySelector("form");
const statusEl = formEl.querySelector(".status-message");
const checkboxGroupEl = formEl.querySelector(".checkbox-group-required");
checkboxGroupEl.addEventListener("click", e => {
statusEl.textContent = validate(checkboxGroupEl) ? "valid" : "invalid";
});
formEl.addEventListener("submit", e => {
e.preventDefault();
if (validate(checkboxGroupEl)) {
statusEl.textContent = "Form submitted!";
// Send data from e.target to your backend
}
else {
statusEl.textContent = "Error: select at least one checkbox";
}
});
<form>
<div class="checkbox-group-required">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
</div>
<input type="submit" />
<div class="status-message"></div>
</form>
If you have multiple groups to validate, add a loop over each group, optionally adding error messages or CSS to indicate which group fails validation:
const validate = el => {
const checkboxes = el.querySelectorAll('input[type="checkbox"]');
return [...checkboxes].some(e => e.checked);
};
const allValid = els => [...els].every(validate);
const formEl = document.querySelector("form");
const statusEl = formEl.querySelector(".status-message");
const checkboxGroupEls = formEl.querySelectorAll(".checkbox-group-required");
checkboxGroupEls.forEach(el =>
el.addEventListener("click", e => {
statusEl.textContent = allValid(checkboxGroupEls) ? "valid" : "invalid";
})
);
formEl.addEventListener("submit", e => {
e.preventDefault();
if (allValid(checkboxGroupEls)) {
statusEl.textContent = "Form submitted!";
}
else {
statusEl.textContent = "Error: select at least one checkbox from each group";
}
});
<form>
<div class="checkbox-group-required">
<label>
Group 1:
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
</label>
</div>
<div class="checkbox-group-required">
<label>
Group 2:
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
</label>
</div>
<input type="submit" />
<div class="status-message"></div>
</form>

I realize there are a ton of solutions here, but I found none of them hit every requirement I had:
No custom coding required
Code works on page load
No custom classes required (checkboxes or their parent)
I needed several checkbox lists to share the same name for submitting Github issues via their API, and was using the name label[] to assign labels across many form fields (two checkbox lists and a few selects and textboxes) - granted I could have achieved this without them sharing the same name, but I decided to try it, and it worked.
The only requirement for this one is jQuery, which could easily be eliminated if you wanted to rewrite it in vanilla JS. You can combine this with #ewall's great solution to add custom validation error messages.
/* required checkboxes */
jQuery(function ($) {
var $requiredCheckboxes = $("input[type='checkbox'][required]");
/* init all checkbox lists */
$requiredCheckboxes.each(function (i, el) {
//this could easily be changed to suit different parent containers
var $checkboxList = $(this).closest("div, span, p, ul, td");
if (!$checkboxList.hasClass("requiredCheckboxList"))
$checkboxList.addClass("requiredCheckboxList");
});
var $requiredCheckboxLists = $(".requiredCheckboxList");
$requiredCheckboxLists.each(function (i, el) {
var $checkboxList = $(this);
$checkboxList.on("change", "input[type='checkbox']", function (e) {
updateCheckboxesRequired($(this).parents(".requiredCheckboxList"));
});
updateCheckboxesRequired($checkboxList);
});
function updateCheckboxesRequired($checkboxList) {
var $chk = $checkboxList.find("input[type='checkbox']").eq(0),
cblName = $chk.attr("name"),
cblNameAttr = "[name='" + cblName + "']",
$checkboxes = $checkboxList.find("input[type='checkbox']" + cblNameAttr);
if ($checkboxList.find(cblNameAttr + ":checked").length > 0) {
$checkboxes.prop("required", false);
} else {
$checkboxes.prop("required", true);
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form method="post" action="post.php">
<div>
Type of report:
</div>
<div>
<input type="checkbox" id="chkTypeOfReportError" name="label[]" value="Error" required>
<label for="chkTypeOfReportError">Error</label>
<input type="checkbox" id="chkTypeOfReportQuestion" name="label[]" value="Question" required>
<label for="chkTypeOfReportQuestion">Question</label>
<input type="checkbox" id="chkTypeOfReportFeatureRequest" name="label[]" value="Feature Request" required>
<label for="chkTypeOfReportFeatureRequest">Feature Request</label>
</div>
<div>
Priority
</div>
<div>
<input type="checkbox" id="chkTypeOfContributionBlog" name="label[]" value="Priority: High" required>
<label for="chkPriorityHigh">High</label>
<input type="checkbox" id="chkTypeOfContributionBlog" name="label[]" value="Priority: Medium" required>
<label for="chkPriorityMedium">Medium</label>
<input type="checkbox" id="chkTypeOfContributionLow" name="label[]" value="Priority: Low" required>
<label for="chkPriorityMedium">Low</label>
</div>
<div>
<input type="submit" />
</div>
</form>

Really simple way to verify if at least one checkbox is checked:
function isAtLeastOneChecked(name) {
let checkboxes = Array.from(document.getElementsByName(name));
return checkboxes.some(e => e.checked);
}
Then you can implement whatever logic you want to display an error.

Here is another simple trick using Jquery!!
HTML
<form id="hobbieform">
<div>
<input type="checkbox" name="hobbies[]">Coding
<input type="checkbox" name="hobbies[]">Gaming
<input type="checkbox" name="hobbies[]">Driving
</div>
</form>
JQuery
$('#hobbieform').on("submit", function (e) {
var arr = $(this).serialize().toString();
if(arr.indexOf("hobbies") < 0){
e.preventDefault();
alert("You must select at least one hobbie");
}
});
That's all.. this works because if none of the checkbox is selected, nothing as regards the checkbox group(including its name) is posted to the server

Pure JS solution:
const group = document.querySelectorAll('[name="myCheckboxGroup"]');
function requireLeastOneChecked() {
var atLeastOneChecked = false;
for (i = 0; i < group.length; i++)
if (group[i].checked)
atLeastOneChecked = true;
if (atLeastOneChecked)
for (i = 0; i < group.length; i++)
group[i].required = false;
else
for (i = 0; i < group.length; i++)
group[i].required = true;
}
requireLeastOneChecked(); // onload
group.forEach(function ($el) {
$el.addEventListener('click', function () { requireLeastOneChecked(); })
});

Hi just use a text box additional to group of check box.When clicking on any check box put values in to that text box.Make that that text box required and readonly.

A general Solution without change the submit event or knowing the name of the checkboxes
Build a Function, which marks the Checkbox as HTML5-Invalid
Extend Change-Event and check validity on the start
jQuery.fn.getSiblingsCheckboxes = function () {
let $this = $(this);
let $parent = $this.closest('form, .your-checkbox-listwrapper');
return $parent.find('input[type="checkbox"][name="' + $this.attr('name')+'"]').filter('*[required], *[data-required]');
}
jQuery.fn.checkRequiredInputs = function() {
return this.each(function() {
let $this = $(this);
let $parent = $this.closest('form, .your-checkbox-list-wrapper');
let $allInputs = $this.getSiblingsCheckboxes();
if ($allInputs.filter(':checked').length > 0) {
$allInputs.each(function() {
// this.setCustomValidity(''); // not needed
$(this).removeAttr('required');
$(this).closest('li').css('color', 'green'); // for debugging only
});
} else {
$allInputs.each(function() {
// this.reportValidity(); // not needed
$(this).attr('required', 'required');
$(this).closest('li').css('color', 'red'); // for debugging only
});
}
return true;
});
};
$(document).ready(function() {
$('input[type="checkbox"][required="required"], input[type="checkbox"][required]').not('*[data-required]').not('*[disabled]').each(function() {
let $input = $(this);
let $allInputs = $input.getSiblingsCheckboxes();
$input.attr('data-required', 'required');
$input.removeAttr('required');
$input.on('change', function(event) {
$input.checkRequiredInputs();
});
});
$('input[type="checkbox"][data-required="required"]').checkRequiredInputs();
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
</head>
<form>
<ul>
<li><input type="checkbox" id="checkbox1" name="countries" value="Argentina" required="required">Argentina</li>
<li><input type="checkbox" id="checkbox2" name="countries" value="France" required="required">France</li>
<li><input type="checkbox" id="checkbox3" name="countries" value="Germany" required="required">Germany</li>
<li><input type="checkbox" id="checkbox4" name="countries" value="Japan" required="required">Japan</li>
<li><input type="checkbox" id="checkbox5" name="countries" value="Australia" required="required">Australia</li>
</ul>
<input type="submit" value="Submit">
</form>

Try:
self.request.get('sports_played', allow_multiple=True)
or
self.request.POST.getall('sports_played')
More specifically:
When you are reading data from the checkbox array, make sure array has:
len>0
In this case:
len(self.request.get('array', allow_multiple=True)) > 0

Store input radio selections when submit is clicked

I need to store in my js file which radio option for each radio name was selected as well as store the Username that was entered. Here is my form
<form id="newPlayer">
Username:<br>
<input type="text" name="user"/><br>
Please Choose a Class: <br>
<input type="radio" name="class"/>Archer
<input type="radio" name="class"/>Mage
<input type="radio" name="class"/>Warrior
<br>
Please Choose a Race: <br>
<input type="radio" name="race"/>Orc
<input type="radio" name="race"/>Elf
<input type="radio" name="race"/>Human
<input type="radio" name="race"/>Worg
<br>
<input type="submit" value="Submit">
</form>
EDIT:
When I try to target the submit button for a click function it causes my page to reload instead of making the form fadeOut
var userInput;
var classInput;
var raceInput;
$('input[type=submit]').click(function(){
$('#newPlayer').fadeOut(500);
userInput = $('input[name="user"]').val();
classInput = $('input[name="class"]:checked').val();
raceInput = $('input[name="race"]:checked').val();
});

Maybe this helps. First, you will have to put values on those inputs
<form id="newPlayer">
Username:<br>
<input type="text" name="user"/><br>
Please Choose a Class: <br>
<input value="archer" type="radio" name="class"/>Archer
<input value="mage" type="radio" name="class"/>Mage
<input value="warrior" type="radio" name="class"/>Warrior
<br>
Please Choose a Race: <br>
<input value="orc" type="radio" name="race"/>Orc
<input value="elf" type="radio" name="race"/>Elf
<input value="human" type="radio" name="race"/>Human
<input value="worg" type="radio" name="race"/>Worg
<br>
<input type="submit" value="Submit">
</form>
Then, using jQuery, a simple .val() will do the job:
var class_val = $('input[name="class"]:checked').val();
var race = $('input[name="race"]:checked').val();
var user = $('input[name="user"]').val();
After that, you just need to put in localStorage
localStorage.setItem('class', class_val);
localStorage.setItem('race', race);
localStorage.setItem('user', user);
To access those values in the future, you do that
var stored_class = localStorage.getItem('class');
var stored_race = localStorage.getItem('race');
var stored_user = localStorage.getItem('user');
To make things happens on submit, you add an submit event to the form, like that:
$('form').on('submit', function() {
// Get values
var class_val = $('input[name="class"]:checked').val();
...
// Store values
localStorage.setItem('class', class_val);
...
// Avoid form submit
return false;
});
Hope it helps :)

I think I would use localStorage.
For example:
//Make sure to set the selection variable to a object that contains the selections made by the user.
function save() {
//This will save the current settings as an object to the localStorage.
localStorage.selections = JSON.stringify(selections) ;
}
function load() {
if (!localStorage.selections) {
alart("No saves found.") ;
return false ;
}
selections = JSON.parse(localStorage.selections) ;
}
Read more about localStorage here.

Javascript adding values to radio buttons to input price

Im trying to create a javascript block inside of a webpage im working on. I havent done javascript since highschool and it doesnt seem to want to come back to me :(
In this block of code i want to have 4 sets of radio buttons, each time a selection is picked,
a price will be inputed to a variable for each radio group. i.e
var firstPrice = $25
var secondPrice = $56
var thirdPrice = $80
var fourthPrice = $90
then after each radio group has one selection there will be a function attached to the submit button that adds up each price to display the final amount inside of a hidden field
var totalPrice = (firstPrice + secondPrice + thirdPrice + fourthPrice)
My question is, how do i attach a number value to a radio button within a group, same name but id is different in each group. Then do i just create a function that adds all the price groups up and then set the submit button to onClick = totalPrice();
Here is an example of one set of radio buttons:
<label>
<input type="radio" name="model" value="radio" id="item_0" />
item 1</label>
<br />
<label>
<input type="radio" name="model" value="radio" id="item_1" />
item2</label>
<br />
<label>
<input type="radio" name="model" value="radio" id="item_2" />
item3</label>
<br />
<label>
<input type="radio" name="model" value="radio" id="item_3" />
Item4</label>
<br />
<label>
<input type="radio" name="model" value="radio" id="item_4" />
item5</label>
</form>
then my script looks something like:
function finalPrice90{
var selectionFirst = document.modelGroup.value;
var selectionSecond = document.secondGroup.value;
var selectionThird = document.thirdGroup.value;
var selectionFourth = document.fourthGroup.Value;
var totalPrice = (selectionFirst + selectionSecond + selectionThird + selectionFourth);
}

Try this fiddle
http://jsfiddle.net/tariqulazam/ZLQXB/

Set the value attribute of your radio inputs to the price each radio button should represent.
When it's time to calculate, simply loop through each group and get the value attribute if the checked radio.
Because the value attribute is a string representation of a number, you'll want to convert it back to a number before doing any math (but that's a simple parseInt or parseFloat).
Here's a working fiddle using pure JavaScript: http://jsfiddle.net/XxZwm/
A library like jQuery or Prototype (or MooTools, script.aculo.us, etc) may make this easier in the long run, depending on how much DOM manipulation code you don't want to re-invent a wheel for.

Your requirements seem pretty simple, here's an example that should answer most questions. There is a single click listener on the form so whenever there is a click on a form control, the price will be updated.
<script type="text/javascript">
//function updatePrice(el) {
function updatePrice(event) {
var el = event.target || event.srcElement;
var form = el.form;
if (!form) return;
var control, controls = form.elements;
var totalPrice = 0;
var radios;
for (var i=0, iLen=controls.length; i<iLen; i++) {
control = controls[i];
if ((control.type == 'radio' || control.type == 'checkbox') && control.checked) {
totalPrice += Number(control.value);
}
// Deal with other types of controls if necessary
}
form.totalPrice.value = '$' + totalPrice;
}
</script>
<form>
<fieldset><legend>Model 1</legend>
<input type="radio" name="model1" value="25">$25<br>
<input type="radio" name="model1" value="35">$35<br>
<input type="radio" name="model1" value="45">$45<br>
<input type="radio" name="model1" value="55">$55<br>
</fieldset>
<fieldset><legend>Model 2</legend>
<input type="radio" name="model2" value="1">$1<br>
<input type="radio" name="model2" value="2">$2<br>
<input type="radio" name="model2" value="3">$3<br>
<input type="radio" name="model2" value="4">$4<br>
<fieldset><legend>Include shipping?</legend>
<span>$5</span><input type="checkbox" value="5" name="shipping"><br>
</fieldset>
<input name="totalPrice" readonly><br>
<input type="reset" value="Clear form">
</form>
You could put a single listener on the form for click events and update the price automatically, in that case you can get rid of the update button.

make checkbox behave like radio buttons with javascript

I need to manipulate the behavior of the check boxes with javascript. They should basically behave like radio buttons (only one selectable at a time, plus unselect any previous selections).
The problem is that I can't use plain radio buttons in first place, because the name attribute for each radio button would be different.
I know its not the ultimate and shiniest solutions to make an apple look like a pear, and w3c wouldn't give me their thumbs for it, but it would be a better solution right now than to change the core php logic of the entire cms structure ;-)
Any help is much appreciated!

HTML :
<label><input type="checkbox" name="cb1" class="chb" /> CheckBox1</label>
<label><input type="checkbox" name="cb2" class="chb" /> CheckBox2</label>
<label><input type="checkbox" name="cb3" class="chb" /> CheckBox3</label>
<label><input type="checkbox" name="cb4" class="chb" /> CheckBox4</label>
jQuery :
$(".chb").change(function() {
$(".chb").prop('checked', false);
$(this).prop('checked', true);
});
if you want user can unchecked selected item :
$(".chb").change(function() {
$(".chb").not(this).prop('checked', false);
});
Demo :
http://jsfiddle.net/44Zfv/724/

There are many ways to do this. This is a clickhandler (plain js) for a div containing a number of checkboxes:
function cbclick(e){
e = e || event;
var cb = e.srcElement || e.target;
if (cb.type !== 'checkbox') {return true;}
var cbxs = document.getElementById('radiocb')
.getElementsByTagName('input'),
i = cbxs.length;
while(i--) {
if (cbxs[i].type
&& cbxs[i].type == 'checkbox'
&& cbxs[i].id !== cb.id) {
cbxs[i].checked = false;
}
}
}
Here's a working example.

This is a better option as it allows unchecking also:
$(".cb").change(function () {
$(".cb").not(this).prop('checked', false);
});

I kept it simple...
<html>
<body>
<script>
function chbx(obj)
{
var that = obj;
if(document.getElementById(that.id).checked == true) {
document.getElementById('id1').checked = false;
document.getElementById('id2').checked = false;
document.getElementById('id3').checked = false;
document.getElementById(that.id).checked = true;
}
}
</script>
<form action="your action" method="post">
<Input id='id1' type='Checkbox' Name ='name1' value ="S" onclick="chbx(this)"><br />
<Input id='id2' type='Checkbox' Name ='name2' value ="S" onclick="chbx(this)"><br />
<Input id='id3' type='Checkbox' Name ='name3' value ="S" onclick="chbx(this)"><br />
<input type="submit" value="Submit" />
</form>
</body>
</html>

#DJafari's answer doesn't let unchecking the checkbox. So I've updated it like this:
$(".chb").change(function(e) {
//Getting status before unchecking all
var status = $(this).prop("checked");
$(".chb").prop('checked', false);
$(this).prop('checked', true);
//false means checkbox was checked and became unchecked on change event, so let it stay unchecked
if (status === false) {
$(this).prop('checked', false);
}
});
https://jsfiddle.net/mapetek/nLtb0q1e/4/

Just in case it helps someone else
I was having the same situation where my client needed to have a checkbox behaving like a radio button. But to me it was meaningless to use a checkbox and make it act like radio button and it was very complex for me as I was using so many checkboxes in a GridView Control.
My Solution: So, I styled a radio button look like a checkbox and took the help of grouping of radio buttons.

You could give the group of checkboxes you need to behave like this a common class, then use the class to attach the following event handler:
function clickReset ()
{
var isChecked = false,
clicked = $(this),
set = $('.' + clicked.attr ('class') + ':checked').not (clicked);
if (isChecked = clicked.attr ('checked'))
{
set.attr ('checked', false);
}
return true;
}
$(function ()
{
$('.test').click (clickReset);
});
Note: This is pretty me just shooting from the hip, I've not tested this and it might need tweaking to work.
I would advise that you do look into finding a way of doing this with radio buttons if you can, as radios are the proper tool for the job. Users expect checkboxes to behave like checkboxes, not radios, and if they turn javascript off they can force through input into the server side script that you weren't expecting.
EDIT: Fixed function so that uncheck works properly and added a JS Fiddle link.
http://jsfiddle.net/j53gd/1/

<html>
<body>
<form action="#" method="post">
Radio 1: <input type="radio" name="radioMark" value="radio 1" /><br />
Radio 2: <input type="radio" name="radioMark" value="radio 2" /><br />
<input type="submit" value="Submit" />
</form>
</body>
</html>
Ultimately you can use brackets with the name attribute to create an array of radio input like so:
<input type="radio" name="radioMark[]" value="radio1" />Radio 1
<input type="radio" name="radioMark[]" value="radio2" />Radio 2
<input type="radio" name="radioMark[]" value="radio3" />Radio 3
<input type="radio" name="radioMark[]" value="radio4" />Radio 4
What matters to transfer in the end are whats in the value attribute. Your names do not have to be different at all for each radio button. Hope that helps.

In Simple JS.
Enjoy !
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function onChoiceChange(obj) {
// Get Objects
var that=obj,
triggerChoice = document.getElementById(that.id),
domChoice1 = document.getElementById("Choice1"),
domChoice2 = document.getElementById("Choice2");
// Apply
if (triggerChoice.checked && triggerChoice.id === "Choice1")
domChoice2.checked=false;
if (triggerChoice.checked && triggerChoice.id === "Choice2")
domChoice1.checked=false;
// Logout
var log = document.getElementById("message");
log.innerHTML += "<br>"+ (domChoice1.checked ? "1" : "0") + ":" + (domChoice2.checked ? "1" : "0");
// Return !
return that.checked;
}
</script>
</head>
<body>
<h1 id="title">Title</h1>
<label><input type="checkbox" onclick="onChoiceChange(this)" id="Choice1" />Choice #1</label>
<label><input type="checkbox" onclick="onChoiceChange(this)" id="Choice2" />Choice #2</label>
<hr>
<div id="message"></div>
</body>
</html>

try this
<form id="form" action="#">
<input name="checkbox1" type="checkbox" />
<input name="checkbox2" type="checkbox" />
<input name="checkbox3" type="checkbox" />
<input name="checkbox4" type="checkbox" />
<input name="checkbox5" type="checkbox" />
<input name="checkbox6" type="checkbox" />
<input name="checkbox7" type="checkbox" />
<input name="checkbox8" type="checkbox" />
<input name="checkbox9" type="checkbox" />
<input name="checkbox10" type="checkbox" />
<input type="submit" name="submit" value="submit"/>
</form>
and this is the javascript
(function () {
function checkLikeRadio(tag) {
var form = document.getElementById(tag);//selecting the form ID
var checkboxList = form.getElementsByTagName("input");//selecting all checkbox of that form who will behave like radio button
for (var i = 0; i < checkboxList.length; i++) {//loop thorough every checkbox and set there value false.
if (checkboxList[i].type == "checkbox") {
checkboxList[i].checked = false;
}
checkboxList[i].onclick = function () {
checkLikeRadio(tag);//recursively calling the same function again to uncheck all checkbox
checkBoxName(this);// passing the location of selected checkbox to another function.
};
}
}
function checkBoxName(id) {
return id.checked = true;// selecting the selected checkbox and maiking its value true;
}
window.onload = function () {
checkLikeRadio("form");
};
})();

I like D.A.V.O.O.D's Answer to this question, but it relies on classes on the checkbox, which should not be needed.
As checkboxes tend to be related in that they will have the same (field) name, or a name which make them part of an array, then using that to decide which other checkboxes to untick would be a better solution.
$(document)
.on('change','input[type="checkbox"]',function(e){
var $t = $(this);
var $form = $t.closest('form');
var name = $t.attr('name');
var selector = 'input[type="checkbox"]';
var m = (new RegExp('^(.+)\\[([^\\]]+)\\]$')).exec( name );
if( m ){
selector += '[name^="'+m[1]+'["][name$="]"]';
}else{
selector += '[name="'+name+'"]';
}
$(selector, $form).not($t).prop('checked',false);
});
This code on jsFiddle