Using the HTML5 "required" attribute for a group of checkboxes?

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"; } });

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"; } });

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. 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); } } });

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.

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

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