Can I use jQuery to check whether at least one checkbox is checked?

Question

I have the following HTML form which can have many checkboxes. When the submit button is clicked, I want the user to get a javascript alert to check at least one checkbox if none are checked. Is there an easy way to do this using jQuery?

<form name = "frmTest" id="frmTest">
  <input type="checkbox" value="true" checked="true" name="chk[120]">
  <input type="checkbox" value="true" checked="true" name="chk[128]">
  <input type="checkbox" name="chk[130]">
  <input type="checkbox" name="chk[143]">
  <input type="submit" name="btnsubmit" value="Submit">
</form>

You would probably be better off with ``. Note also that the **only** acceptable value for the checked attribute is "checked". `checked="true"` is an error. — Quentin, Apr 21 '10 at 16:22

Quentin · Answer 1 · 2015-12-17T14:21:49.377

106

if(jQuery('#frmTest input[type=checkbox]:checked').length) { … }

edited Dec 17 '15 at 14:21

answered Apr 21 '10 at 15:51

Quentin

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:checked already returns a boolean, so .length is not needed. true.length and false.length both provide undefined – Jan Mar 21 '14 at 12:30
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@Jan — `jQuery('#frmTest input[type=checkbox]:checked')` returns a jQuery object containing all the elements that match the selector. It does not return a boolean. You might be confusing it with `HTMLInputElement.checked`. – Quentin Mar 21 '14 at 12:33

Matthew Flaschen · Answer 2 · 2010-09-15T17:23:30.233

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$('#frmTest input:checked').length > 0

edited Sep 15 '10 at 17:23

answered Apr 21 '10 at 15:50

Matthew Flaschen

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$('#frmTest:checkbox').length > 0 would be better to check among a certain number of checkboxes. – Kasturi Apr 21 '10 at 15:54
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Why would radio-buttons be better? If the OP wants *at least* one option selected radio-buttons would limit him to one *at most*. – David Thomas Sep 15 '10 at 16:39
1

@David, I've removed that suggestion. – Matthew Flaschen Sep 15 '10 at 17:24

score 24 · Answer 3 · answered Apr 21 '10 at 15:51

24

$("#frmTest").submit(function(){
    var checked = $("#frmText input:checked").length > 0;
    if (!checked){
        alert("Please check at least one checkbox");
        return false;
    }
});

answered Apr 21 '10 at 15:51

Jon

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score 10 · Answer 4 · answered May 08 '13 at 08:31

10

$("#show").click(function() {
    var count_checked = $("[name='chk[]']:checked").length; // count the checked rows
        if(count_checked == 0) 
        {
            alert("Please select any record to delete.");
            return false;
        }
        if(count_checked == 1) {
            alert("Record Selected:"+count_checked);

        } else {
            alert("Record Selected:"+count_checked);
          }
});

answered May 08 '13 at 08:31

chithon

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Doesn't work for me, something changed in how jQuery handles checkbox checked event? – Envayo Jun 05 '17 at 12:02

score 7 · Answer 5 · edited Sep 29 '17 at 15:42

$('#fm_submit').submit(function(e){
    e.preventDefault();
    var ck_box = $('input[type="checkbox"]:checked').length;
    
    // return in firefox or chrome console 
    // the number of checkbox checked
    console.log(ck_box); 

    if(ck_box > 0){
      alert(ck_box);
    } 
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form name = "frmTest[]" id="fm_submit">
  <input type="checkbox" value="true" checked="true" >
  <input type="checkbox" value="true" checked="true" >
  <input type="checkbox" >
  <input type="checkbox" >
  <input type="submit" id="fm_submit" name="fm_submit" value="Submit">
</form>
<div class="container"></div>

score 6 · Answer 6 · answered Sep 15 '10 at 16:34

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$('#frmTest').submit(function(){
    if(!$('#frmTest input[type="checkbox"]').is(':checked')){
      alert("Please check at least one.");
      return false;
    }
});

is(':checked') will return true if at least one or more of the checkboxes are checked.

answered Sep 15 '10 at 16:34

neveraskedforthis

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Is it possible for this to check on live checkbox clicks? – Robert Jul 09 '12 at 22:12
Yes, but you would use a different event handler. See this: http://stackoverflow.com/questions/3442322/jquery-checkbox-event-handling – neveraskedforthis Jan 30 '13 at 17:01

Can I use jQuery to check whether at least one checkbox is checked?

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