Check if checkbox is checked with jQuery

Question

How can I check if a checkbox in a checkbox array is checked using the id of the checkbox array?

I am using the following code, but it always returns the count of checked checkboxes regardless of id.

function isCheckedById(id) {
  alert(id);
  var checked = $("input[@id=" + id + "]:checked").length;
  alert(checked);

  if (checked == 0) {
    return false;
  } else {
    return true;
  }
}

Answer 1

Just to say in my example the situation was a dialog box that then verified the check box before closing dialog. None of above and How to check whether a checkbox is checked in jQuery? and jQuery if checkbox is checked did not appear to work either.

In the end

<input class="cb" id="rd" type="checkbox">
<input class="cb" id="fd" type="checkbox">

var fd=$('.cb#fd').is(':checked');
var rd= $('.cb#rd').is(':checked');

This worked so calling the class then the ID. rather than just the ID. It may be due to the nested DOM elements on this page causing the issue. The workaround was above.

Answer 2

Toggle checkbox checked

$("#checkall").click(function(){
    $("input:checkbox").prop( 'checked',$(this).is(":checked") );
})

Answer 3

I know the OP want jquery but in my case pure JS was the answer so if anyone like me is here and do not have jquery or do not want to use it - here is the JS answer:

document.getElementById("myCheck").checked

It returns true if the input with ID myCheck is checked and false if it is not checked.

Simple as that.

Answer 4

Something like this can help

togglecheckBoxs =  function( objCheckBox ) {

    var boolAllChecked = true;

    if( false == objCheckBox.checked ) {
        $('#checkAll').prop( 'checked',false );
    } else {
        $( 'input[id^="someIds_"]' ).each( function( chkboxIndex, chkbox ) {
            if( false == chkbox.checked ) {
                $('#checkAll').prop( 'checked',false );
                boolAllChecked = false;
            }
        });

        if( true == boolAllChecked ) {
            $('#checkAll').prop( 'checked',true );
        }
    }
}

Answer 5

The most important concept to remember about the checked attribute is that it does not correspond to the checked property. The attribute actually corresponds to the defaultChecked property and should be used only to set the initial value of the checkbox. The checked attribute value does not change with the state of the checkbox, while the checked property does. Therefore, the cross-browser-compatible way to determine if a checkbox is checked is to use the property

All below methods are possible

elem.checked 

$(elem).prop("checked") 

$(elem).is(":checked") 

Answer 6

Using this code you can check at least one checkbox is selected or not in different checkbox groups or from multiple checkboxes. Using this you can not require to remove IDs or dynamic IDs. This code work with the same IDs.

Reference Link

<label class="control-label col-sm-4">Check Box 2</label>
    <input type="checkbox" name="checkbox2" id="checkbox21" value=ck1 /> ck1<br />
    <input type="checkbox" name="checkbox2" id="checkbox22" value=ck2 /> ck2<br />

<label class="control-label col-sm-4">Check Box 3</label>
    <input type="checkbox" name="checkbox3" id="checkbox31" value=ck3 /> ck3<br />
    <input type="checkbox" name="checkbox3" id="checkbox32" value=ck4 /> ck4<br />

<script>
function checkFormData() {
    if (!$('input[name=checkbox2]:checked').length > 0) {
        document.getElementById("errMessage").innerHTML = "Check Box 2 can not be null";
        return false;
    }
    if (!$('input[name=checkbox3]:checked').length > 0) {
        document.getElementById("errMessage").innerHTML = "Check Box 3 can not be null";
        return false;
    }
    alert("Success");
    return true;
}
</script>