Answers for "on checked jquery"

jquery checkbox checked

$("checkbox").is(":checked")

oncheck event jquery

$(".checkbox").change(function() {
    if(this.checked) {
        //Do stuff
    }
});

jquery is checked

if ($('[name="your_input_checkbox_name"]').is(":checked"))
{
  // it is checked
} else {
  // it isn't checked	
}