checkbox is checked check code example
Example 1: jquery check if checkbox is checked
if($('#on_or_off_checkbox').is(':checked')){
//I am checked
}
Example 2: how to check input is selected or not
$('#' + id).is(":checked")
if($('#on_or_off_checkbox').is(':checked')){
//I am checked
}
$('#' + id).is(":checked")