how to get count of selected checkbox in jquery code example

Example 1: get value of selected checkbox jquery

$('#checkbox_id:checked').val();
//if checkbox is selected than gets its value

Example 2: count number of checkboxes in html jquery

var numberOfChecked = $('input:checkbox:checked').length;
var totalCheckboxes = $('input:checkbox').length;
var numberNotChecked = totalCheckboxes - numberOfChecked;