jQuery SelectBox plugin, with _slight_ modifications

jquery.selectbox.js

/**
 * jQuery Selectbox plugin 0.1
 *
 * Copyright 2011, Dimitar Ivanov (http://www.bulgaria-web-developers.com/projects/javascript/selectbox/)
 * Licensed under the MIT (http://www.opensource.org/licenses/mit-license.php) license.
 */
(function ($, undefined) {
	var PROP_NAME = 'selectbox',
		FALSE = false,
		TRUE = true;
	/**
	 * Selectbox manager.
	 * Use the singleton instance of this class, $.selectbox, to interact with the select box.
	 * Settings for (groups of) select boxes are maintained in an instance object,
	 * allowing multiple different settings on the same page
	 */
	function Selectbox() {
		this._state = [];
		this._defaults = { // Global defaults for all the select box instances
			classHolder: "sbHolder",
			classHolderDisabled: "sbHolderDisabled",
			classSelector: "sbSelector",
			classOptions: "sbOptions",
			classToggleOpen: "sbToggleOpen",
			classToggle: "sbToggle",
			effect: "slide", // "slide" or "fade"
			onChange: null, //Define a callback function when the selectbox is changed
			onOpen: null, //Define a callback function when the selectbox is open
			onClose: null //Define a callback function when the selectbox is closed
		};
	}
	
	$.extend(Selectbox.prototype, {
		/**
		 * Is the first field in a jQuery collection open as a selectbox
		 * 
		 * @param {Object} target
		 * @return {Boolean}
		 */
		_isOpenSelectbox: function (target) {
			if (!target) {
				return FALSE;
			}
			var inst = this._getInst(target);
			return inst.isOpen;
		},
		/**
		 * Is the first field in a jQuery collection disabled as a selectbox
		 * 
		 * @param {HTMLElement} target
		 * @return {Boolean}
		 */
		_isDisabledSelectbox: function (target) {
			if (!target) {
				return FALSE;
			}
			var inst = this._getInst(target);
			return inst.isDisabled;
		},
		/**
		 * Attach the select box to a jQuery selection.
		 * 
		 * @param {HTMLElement} target
		 * @param {Object} settings
		 */
		_attachSelectbox: function (target, settings) {
			if (this._getInst(target)) {
				return FALSE;
			}
			var $target = $(target),
				self = this,
				inst = self._newInst($target),
				sbHolder, sbSelector, sbToggle, sbOptions,
				s = FALSE, opts = $target.find("option"), olen = opts.length;
			$.extend(inst.settings, self._defaults, settings);
			self._state[inst.uid] = FALSE;
			$target.hide();
			sbHolder = $("<div>", {
				"id": "sbHolder_" + inst.uid,
				"class": inst.settings.classHolder,
				"focusin": function () {
					var key, uid = $(this).attr("id").split("_")[1];
					for (key in self._state) {
						if (key !== uid) {
							if (self._state.hasOwnProperty(key)) {
								$("#sbOptions_" + key).hide();
								$("#sbToggle_" + key).removeClass(inst.settings.classToggleOpen);
								self._state[key] = FALSE;
							}
						}
					}
				}
			});
			
			sbSelector = $("<a>", {
				"id": "sbSelector_" + inst.uid,
				"href": "#",
				"class": inst.settings.classSelector,
				"click": function (e) {
					e.preventDefault();
					var uid = $(this).attr("id").split("_")[1];
					if (self._state[uid]) {
						self._closeSelectbox(target);
					} else {
						self._openSelectbox(target);
					}
				}
			});
			
			sbToggle = $("<a>", {
				"id": "sbToggle_" + inst.uid,
				"href": "#",
				"class": inst.settings.classToggle,
				"click": function (e) {
					e.preventDefault();
					var uid = $(this).attr("id").split("_")[1];
					if (self._state[uid]) {
						self._closeSelectbox(target);
					} else {
						self._openSelectbox(target);
					}
				}
			});
			sbToggle.appendTo(sbHolder);

			sbOptions = $("<ul>", {
				"id": "sbOptions_" + inst.uid,
				"class": inst.settings.classOptions,
				"css": {
					"display": "none"
				}
			});
			
			opts.each(function (i) {
				var that = $(this),
					li = $("<li>");
				if (that.is(":selected")) {
					sbSelector.text(that.text());
					s = TRUE;
				}
				if (i === olen - 1) {
					li.addClass("last");
				}
				$("<a>", {
					"href": "#" + that.val(),
					"rel": that.val(), 
					"text": that.text(),
					"click": function (e) {
						e.preventDefault();
						var t = sbToggle,
							uid = t.attr("id").split("_")[1];
						self._changeSelectbox(target, $(this).attr("rel"), $(this).text());
						self._closeSelectbox(target);
					}
				}).appendTo(li);
				li.appendTo(sbOptions);
			});
			if (!s) {
				sbSelector.text(opts.first().text());
			}
			
			$.data(target, PROP_NAME, inst);
			
			sbSelector.appendTo(sbHolder);
			sbOptions.appendTo(sbHolder);			
			sbHolder.insertAfter($target);
		},
		/**
		 * Remove the selectbox functionality completely. This will return the element back to its pre-init state.
		 * 
		 * @param {HTMLElement} target
		 */
		_detachSelectbox: function (target) {
			var inst = this._getInst(target);
			if (!inst) {
				return FALSE;
			}
			$("#sbHolder_" + inst.uid).remove();
			$.data(target, PROP_NAME, null);
			$(target).show();			
		},
		/**
		 * Change selected attribute of the selectbox.
		 * 
		 * @param {HTMLElement} target
		 * @param {String} value
		 * @param {String} text
		 */
		_changeSelectbox: function (target, value, text) {
			var inst = this._getInst(target),
				onChange = this._get(inst, 'onChange');
			$("#sbSelector_" + inst.uid).text(text);
			$(target).children("option[value='" + value + "']").attr("selected", TRUE);
			if (onChange) {
				onChange.apply((inst.input ? inst.input[0] : null), [value, inst]);
			} else if (inst.input) {
				inst.input.trigger('change');
			}
		},
		/**
		 * Enable the selectbox.
		 * 
		 * @param {HTMLElement} target
		 */
		_enableSelectbox: function (target) {
			var inst = this._getInst(target);
			if (!inst || !inst.isDisabled) {
				return FALSE;
			}
			$("#sbHolder_" + inst.uid).removeClass(inst.settings.classHolderDisabled);
			inst.isDisabled = FALSE;
			$.data(target, PROP_NAME, inst);
		},
		/**
		 * Disable the selectbox.
		 * 
		 * @param {HTMLElement} target
		 */
		_disableSelectbox: function (target) {
			var inst = this._getInst(target);
			if (!inst || inst.isDisabled) {
				return FALSE;
			}
			$("#sbHolder_" + inst.uid).addClass(inst.settings.classHolderDisabled);
			inst.isDisabled = TRUE;
			$.data(target, PROP_NAME, inst);
		},
		/**
		 * Get or set any selectbox option. If no value is specified, will act as a getter.
		 * 
		 * @param {HTMLElement} target
		 * @param {String} name
		 * @param {Object} value
		 */
		_optionSelectbox: function (target, name, value) {
			var inst = this._getInst(target);
			if (!inst) {
				return FALSE;
			}
			//TODO check name
			inst[name] = value;
			$.data(target, PROP_NAME, inst);
		},
		/**
		 * Call up attached selectbox
		 * 
		 * @param {HTMLElement} target
		 */
		_openSelectbox: function (target) {
			var inst = this._getInst(target);
			//if (!inst || this._state[inst.uid] || inst.isDisabled) {
			if (!inst || inst.isOpen || inst.isDisabled) {
				return;
			}
			var	el = $("#sbOptions_" + inst.uid),
				viewportHeight = parseInt($(window).height(), 10),
				offset = $("#sbHolder_" + inst.uid).offset(),
				scrollTop = $(window).scrollTop(),
				height = el.prev().outerHeight(),
				diff = viewportHeight - (offset.top - scrollTop) - height / 2,
				onOpen = this._get(inst, 'onOpen');
			el.css({
				"top": height + "px",
				"maxHeight": (diff - height) + "px"
			});
			inst.settings.effect === "fade" ? el.fadeIn() : el.slideDown();
			$("#sbToggle_" + inst.uid).addClass(inst.settings.classToggleOpen);
			this._state[inst.uid] = TRUE;
			inst.isOpen = TRUE;
			if (onOpen) {
				onOpen.apply((inst.input ? inst.input[0] : null), [inst]);
			}
			$.data(target, PROP_NAME, inst);
		},
		/**
		 * Close opened selectbox
		 * 
		 * @param {HTMLElement} target
		 */
		_closeSelectbox: function (target) {
			var inst = this._getInst(target);
			//if (!inst || !this._state[inst.uid]) {
			if (!inst || !inst.isOpen) {
				return;
			}
			var onClose = this._get(inst, 'onClose');
			inst.settings.effect === "fade" ? $("#sbOptions_" + inst.uid).fadeOut() : $("#sbOptions_" + inst.uid).slideUp();
			$("#sbToggle_" + inst.uid).removeClass(inst.settings.classToggleOpen);
			this._state[inst.uid] = FALSE;
			inst.isOpen = FALSE;
			if (onClose) {
				onClose.apply((inst.input ? inst.input[0] : null), [inst]);
			}
			$.data(target, PROP_NAME, inst);
		},
		/**
		 * Create a new instance object
		 * 
		 * @param {HTMLElement} target
		 * @return {Object}
		 */
		_newInst: function(target) {
			var id = target[0].id.replace(/([^A-Za-z0-9_-])/g, '\\\\$1');
			return {
				id: id, 
				input: target, 
				uid: Math.floor(Math.random() * 99999999),
				isOpen: FALSE,
				isDisabled: FALSE,
				settings: {}
			}; 
		},
		/**
		 * Retrieve the instance data for the target control.
		 * 
		 * @param {HTMLElement} target
		 * @return {Object} - the associated instance data
		 * @throws error if a jQuery problem getting data
		 */
		_getInst: function(target) {
			try {
				return $.data(target, PROP_NAME);
			}
			catch (err) {
				throw 'Missing instance data for this selectbox';
			}
		},
		/**
		 * Get a setting value, defaulting if necessary
		 * 
		 * @param {Object} inst
		 * @param {String} name
		 * @return {Mixed}
		 */
		_get: function(inst, name) {
			return inst.settings[name] !== undefined ? inst.settings[name] : this._defaults[name];
		}
	});

	/**
	 * Invoke the selectbox functionality.
	 * 
	 * @param {Object|String} options
	 * @return {Object}
	 */
	$.fn.selectbox = function (options) {
		
		var otherArgs = Array.prototype.slice.call(arguments, 1);
		if (typeof options == 'string' && options == 'isDisabled') {
			return $.selectbox['_' + options + 'Selectbox'].apply($.selectbox, [this[0]].concat(otherArgs));
		}
		
		if (options == 'option' && arguments.length == 2 && typeof arguments[1] == 'string') {
			return $.selectbox['_' + options + 'Selectbox'].apply($.selectbox, [this[0]].concat(otherArgs));
		}
		
		return this.each(function() {
			typeof options == 'string' ?
				$.selectbox['_' + options + 'Selectbox'].apply($.selectbox, [this].concat(otherArgs)) :
				$.selectbox._attachSelectbox(this, options);
		});
	};
	
	$.selectbox = new Selectbox(); // singleton instance
	$.selectbox.version = "0.1";
})(jQuery);