Get the value of checked checkbox?

Question

So I've got code that looks like this:

<input class="messageCheckbox" type="checkbox" value="3" name="mailId[]">
<input class="messageCheckbox" type="checkbox" value="1" name="mailId[]">

I just need Javascript to get the value of whatever checkbox is currently checked.

EDIT: To add, there will only be ONE checked box.

Answer 1

None of the above worked for me but simply use this:

document.querySelector('.messageCheckbox').checked;

Answer 2

For modern browsers:

var checkedValue = document.querySelector('.messageCheckbox:checked').value;

By using jQuery:

var checkedValue = $('.messageCheckbox:checked').val();

Pure javascript without jQuery:

var checkedValue = null; 
var inputElements = document.getElementsByClassName('messageCheckbox');
for(var i=0; inputElements[i]; ++i){
      if(inputElements[i].checked){
           checkedValue = inputElements[i].value;
           break;
      }
}

Answer 3

I am using this in my code.Try this

var x=$("#checkbox").is(":checked");

If the checkbox is checked x will be true otherwise it will be false.

Answer 4

in plain javascript:

function test() {
    var cboxes = document.getElementsByName('mailId[]');
    var len = cboxes.length;
    for (var i=0; i<len; i++) {
        alert(i + (cboxes[i].checked?' checked ':' unchecked ') + cboxes[i].value);
    }
}

function selectOnlyOne(current_clicked) {
    var cboxes = document.getElementsByName('mailId[]');
    var len = cboxes.length;
    for (var i=0; i<len; i++) {
        cboxes[i].checked = (cboxes[i] == current);
    }
}

Answer 5

This does not directly answer the question, but may help future visitors.

---

If you want to have a variable always be the current state of the checkbox (rather than having to keep checking its state), you can modify the onchange event to set that variable.

This can be done in the HTML:

<input class='messageCheckbox' type='checkbox' onchange='some_var=this.checked;'>

or with JavaScript:

cb = document.getElementsByClassName('messageCheckbox')[0]
cb.addEventListener('change', function(){some_var = this.checked})

Answer 6

$(document).ready(function() {
  var ckbox = $("input[name='ips']");
  var chkId = '';
  $('input').on('click', function() {
    
    if (ckbox.is(':checked')) {
      $("input[name='ips']:checked").each ( function() {
      chkId = $(this).val() + ",";
        chkId = chkId.slice(0, -1);
    });
       
       alert ( $(this).val() ); // return all values of checkboxes checked
       alert(chkId); // return value of checkbox checked
    }     
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<input type="checkbox" name="ips" value="12520">
<input type="checkbox" name="ips" value="12521">
<input type="checkbox" name="ips" value="12522">

Answer 7

Use this:

alert($(".messageCheckbox").is(":checked").val())

This assumes the checkboxes to check have the class "messageCheckbox", otherwise you would have to do a check if the input is the checkbox type, etc.

Answer 8

<input class="messageCheckbox" type="checkbox" onchange="getValue(this.value)" value="3" name="mailId[]">

<input class="messageCheckbox" type="checkbox" onchange="getValue(this.value)" value="1" name="mailId[]">

function getValue(value){
    alert(value);
}

Answer 9

None of the above worked for me without throwing errors in the console when the box wasn't checked so I did something along these lines instead (onclick and the checkbox function are only being used for demo purposes, in my use case it's part of a much bigger form submission function):

function checkbox() {
  var checked = false;
  if (document.querySelector('#opt1:checked')) {
     checked = true;
  }
  document.getElementById('msg').innerText = checked;
}

<input type="checkbox" onclick="checkbox()" id="opt1"> <span id="msg">Click The Box</span>

Answer 10

if you using after an event occurred you can use

const selected = event.target.checked; //true or false

An example would be if you want to track selected items, here is an example using react react-hook-form react material ui, it would be better than using value from rendered field that give wrong values

...
const [selectedQuestions, setSelectedQuestions] = useState(0);

const handleSelectedQuestions = (checked) => {
  if (checked) {
    setSelectedQuestions((prev) => prev + 1);
  } else {
    setSelectedQuestions((prev) => prev - 1);
  }
};

<Controller
  key={item.id}
  control={control}
  name={`question-${item.id}`}
  defaultValue={false}
  render={({ field: { onChange } }) => (
    <Grid key={item.id} item xs={12}>
      <QuestionCard
        item={item}
        handleOpen={handleOpen}
        isLoading={isLoading}
        isError={isError}
        onChange={(event) => {
          handleSelectedQuestions(event.target.checked);
          onChange(event);
        }}
      />
    </Grid>
  )}
/>
...

export default function QuestionsCard({ item, handleOpen, onChange }) {
  return (    
    ...
    <FormControlLabel
      control={
        <Checkbox
          // checked={value}
          onChange={onChange}
          sx={{
            '& svg': {
              fontSize: '1.266rem',
            },
          }}
        />
      }
    />
  )
}

Answer 11

If you're using Semantic UI React, data is passed as the second parameter to the onChange event.

You can therefore access the checked property as follows:

<Checkbox label="Conference" onChange={(e, d) => console.log(d.checked)} />

Answer 12

If you want to get the values of all checkboxes using jQuery, this might help you. This will parse the list and depending on the desired result, you can execute other code. BTW, for this purpose, one does not need to name the input with brackets []. I left them off.

  $(document).on("change", ".messageCheckbox", function(evnt){
    var data = $(".messageCheckbox");
    data.each(function(){
      console.log(this.defaultValue, this.checked);
      // Do something... 
    });
  }); /* END LISTENER messageCheckbox */

Answer 13

pure javascript and modern browsers

// for boolean
document.querySelector(`#isDebugMode`).checked

// checked means specific values
document.querySelector(`#size:checked`)?.value ?? defaultSize

Example

<form>
  <input type="checkbox" id="isDebugMode"><br>
  <input type="checkbox" value="3" id="size"><br>
  <input type="submit">
</form>

<script>
  document.querySelector(`form`).onsubmit = () => {
    const isDebugMode = document.querySelector(`#isDebugMode`).checked
    const defaultSize = "10"
    const size = document.querySelector(`#size:checked`)?.value ?? defaultSize
    //  for defaultSize is undefined or null
    // const size = document.querySelector(`#size:checked`)?.value
    console.log({isDebugMode, size})
    return false
  }
</script>

• Optional_chaining (?.)

Answer 14

Surprised to see no working vanilla JavaScript solutions here (the top voted answer does not work when you follow best practices and use different IDs for each HTML element). However, this did the job for me:

Array.prototype.slice.call(document.querySelectorAll("[name='mailId']:checked"),0).map(function(v,i,a) { 
      return v.value; 
  });

Answer 15

You could use following ways via jQuery or JavaScript to check whether checkbox is clicked.

$('.messageCheckbox').is(":checked"); // jQuery
document.getElementById(".messageCheckbox").checked //JavaScript

To obtain the value checked in jQuery:

$(".messageCheckbox").is(":checked").val();

Answer 16

In my project, I usually use this snippets:

var type[];
$("input[name='messageCheckbox']:checked").each(function (i) {
                type[i] = $(this).val();
            });

And it works well.