Togglefrog.js
Copyright 2011 Mike McNally - All Rights Reserved

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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Togglefrog is a jQuery plugin designed to handle the common web form situation
of page sections under the control of radio buttons, checkboxes, or pulldowns.
By "under the control", I mean that the style and interaction properties of
some section of the page change based on whether some other control (a radio
button, checkbox, or select) is active (checked or selected).

Using togglefrog, elements involved are considered to be either "togglers" or
"toggled".  The "toggler" elements are those that control the "toggled"
elements.  When setting up toggling, it's the "toggled" elements that are
selected with jQuery, and the "togglers" are determined by options.

Togglefrog can be used like any other jQuery plugin:

    $(selector).togglefrog(options);

That puts each matched page element under control of one or more radio buttons,
checkboxes, or select elements, according to the given options. Certain of the
options, including the most important ones, are by default taken from "data-"
attributes on the affected elements. Here are the available options:

  toggler: identifies the toggler element(s) for the toggled element. The
    value of "toggler" is in the simplest case a single "id" string. Such a 
    setup is quite common: a portion of the page is toggled by a single
    control (radio button, checkbox, or option).  The toggler value can
    also be a list of "id" values, separated by commas.  Such a list means
    that the toggled element should be considered toggled (that is, "on",
    conceptually) if *all* the referenced toggler elements are checked or
    selected.  Finally, the toggler value can be a list of such lists,
    separated by semicolons. Such a list of lists means that the toggled
    element is considered to be toggled when *any* of the sublists are
    all checked or selected.  In other words, "," is like "and" and ";"
    is like "or".  In all cases, an "id" value preceded by an exclamation
    point reverses the sense of that toggler element's "checked" or
    "selected" value, allowing a toggled element to be "on" when its
    controlling toggler is "off".  The attribute "data-toggler" on the
    toggled element can provide this option value.

  toggledClass: a space-separated list of class names to be added to the
    toggled element when it's toggled "on" and removed when "off". By
    default, the class name "toggled" is added/removed.

  untoggledClass: a space-separated list of class names to be added to
    the toggled element when it's toggled "off" and removed when "on".
    By default, the class name "untoggled" is added/removed.

  toggleDisable: a "true" or "false" value indicating whether, when
    the toggled element is "off", all input, select, and textarea elements
    within it are marked as "disabled". It's common to want inputs 
    dsabled when a form section is toggled "off" because they're thus
    irrelevant, but the behavior is optional.

  whenToggled: a function to be called whenever the toggled element is
    toggled "on". The function is called with the toggled element as the
    context (the value of "this"). The function is passed a boolean flag
    indicating whether the element is *fully* toggled "on", which is true
    when the element and all toggled parents (if any) are "on".

  whenUntoggled: a function to be called whenever the toggled element is
    untoggled ("off").

  togglerClass: class name to add to toggler elements. The default class
    is "toggler".