Below code snippet explains how to find out whether a particular HTML input checkbox is checked or unchecked using jQuery
<input type = "checkbox" id = "chk" checked = "checked" />
<input type = "button" id = "demo" value = "Demo" />
 
<script type = "text/javascript" src = "http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.6.1.min.js"></script>
<script type="text/javascript">
    $("#demo").live("click", function () {
        if ($("#chk").is(":checked")) {
            alert("Checkbox is checked");
        } else {
            alert("Checkbox is unchecked");
        }
    });
</script>
 
 
Explanation:
In the above example a click event handler has been assigned to the HTML input button. When the button is clicked, the checked state of the HTML input checkbox with id “chk” is determined using jQuery and displayed in alert using the :checked property.