How to check if a checkbox is checked

var is_checked = $('input[type=checkbox]').is(':checked');

is_checked - this variable will contain true if selected checkbox if checked
$('input\[type=checkbox\]') - jQuery selector (box) for needed checkbox element
.is( - checks selected element with specified selector
:checked - selector for checked elements

link_youtube: https://youtu.be/JiEZ8Z6I5tY