The below code snippet explains how to get all checked or selected HTML input checkboxes in the whole HTML document.
<input type="checkbox" id="Checkbox1" value = "1" />
<input type="checkbox" id="Checkbox2" value = "2" />
<input type="checkbox" id="Checkbox3" value = "3" />
<input type="checkbox" id="Checkbox4" value = "4" />
<input type="button" id="Button1" value = "Demo" />
<script type = "text/javascript" src = ""></script>
<script type="text/javascript">
    $("#demo").live("click", function () {
        $("input:checkbox:checked").each(function () {
            alert("Id: " + $(this).attr("id") + " Value: " + $(this).val());
In the above example a click event handler has been assigned to the HTML input button. When the button is clicked, jQuery finds all the checked  or selected checkboxes within the HTML document and that are using input:checkbox:checked selector and then the Id and value attribute of the all HTML input checkboxes are displayed in alert using jQuery.