Simple way to bind the state of a checkbox to an associated function.

jquery.bindcheckbox.js

// Bind a checkbox to a with checked and unchecked callback functions
// and run the appropriate action on page load:
// 
// Examples
// 
//   $("input[type=checkbox][name=thecheckbox]").bindCheckbox({
//       checked: function() {
//           alert("the checkbox is checked!")
//       },
//       unchecked: function() {
//           alert("the checkbox isn't checked!")
//       }
//   })
// 
// Returns chainable jQuery object
$.fn.bindCheckbox = function(options) {
    return this.each(function() { 
        $(this).change(function() {
            if ($(this).filter(':checked').val()) {
                options.checked();
            } else {
                options.unchecked();
            }
        }).trigger('change');
    });
}