How do I check whether a checkbox is checked in jQuery?

Question

I need to check the checked property of a checkbox and perform an action based on the checked property using jQuery.

For example, if the age checkbox is

Answer 1

Using the Click event handler for the checkbox property is unreliable, as the checked property can change during the execution of the event handler itself!

Ideally, you'd want to put your code into a change event handler such as it is fired every time the value of the check box is changed (independent of how it's done so).

$('#isAgeSelected').bind('change', function () {

   if ($(this).is(':checked'))
     $("#txtAge").show();
   else
     $("#txtAge").hide();
});

Answer 2

This is some different method to do the same thing:

$(document).ready(function (){

    $('#isAgeSelected').click(function() {
        // $("#txtAge").toggle(this.checked);

        // Using a pure CSS selector
        if ($(this.checked)) {
            alert('on check 1');
        };

        // Using jQuery's is() method
        if ($(this).is(':checked')) {
            alert('on checked 2');
        };

        //  // Using jQuery's filter() method
        if ($(this).filter(':checked')) {
            alert('on checked 3');
        };
    });
});

<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<input type="checkbox" id="isAgeSelected"/>
<div id="txtAge" style="display:none">Age is something</div>

Answer 3

$(document).ready(function() {    
    $('#agecheckbox').click(function() {
        if($(this).is(":checked"))
        {
            $('#agetextbox').show();
        } else {
            $('#agetextbox').hide();
        }
    });
});

Answer 4

I believe you could do this:

if ($('#isAgeSelected :checked').size() > 0)
{
    $("#txtAge").show(); 
} else { 
    $("#txtAge").hide();
}

Answer 5

I am using this and this is working absolutely fine:

$("#checkkBoxId").attr("checked") ? alert("Checked") : alert("Unchecked");

Note: If the checkbox is checked it will return true otherwise undefined, so better check for the "TRUE" value.

Answer 6

This code will help you

$('#isAgeSelected').click(function(){
   console.log(this.checked);
   if(this.checked == true) {
        $("#txtAge").show();
    } else {
       $("#txtAge").hide();
   }
});