jQuery checkbox event handling

$('#myform :checkbox').change(function() {
    // this will contain a reference to the checkbox   
    if (this.checked) {
        // the checkbox is now checked 
    } else {
        // the checkbox is now no longer checked
    }
});

Use the change event.

$('#myform :checkbox').change(function() {
    // this represents the checkbox that was checked
    // do something with it
});