How do I check whether a checkbox is checked in jQuery?

Question

I need to check the checked property of a checkbox and perform an action based on the checked property using jQuery.

For example, if the age checkbox is

Answer 1

Using jQuery > 1.6

// traditional attr
$('#checkMeOut').attr('checked'); // "checked"
// new property method
$('#checkMeOut').prop('checked'); // true

Using the new property method:

if($('#checkMeOut').prop('checked')) {
    // something when checked
} else {
    // something else when not
}