Answers for "get checkbox checked value in jquery"

jquery checkbox is checked

//using plane javascript 
if(document.getElementById('on_or_off_checkbox').checked) {
    //I am checked
} 

//using jQuery
if($('#on_or_off_checkbox').is(':checked')){
    //I am checked
}

get value of selected checkbox jquery

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