# Yahoo! UI Library

### Menu 2.2.2

Yahoo! UI Library > menu > menubar.js (source view)

    /**
    * Horizontal collection of items, each of which can contain a submenu.
    *
    * @param {String} p_oElement String specifying the id attribute of the
    * <code>&#60;div&#62;</code> element of the menu bar.
    * @param {String} p_oElement String specifying the id attribute of the
    * <code>&#60;select&#62;</code> element to be used as the data source for the
    * menu bar.
    * @param {<a href="http://www.w3.org/TR/2000/WD-DOM-Level-1-20000929/level-
    * one-html.html#ID-22445964">HTMLDivElement</a>} p_oElement Object specifying
    * the <code>&#60;div&#62;</code> element of the menu bar.
    * @param {<a href="http://www.w3.org/TR/2000/WD-DOM-Level-1-20000929/level-
    * one-html.html#ID-94282980">HTMLSelectElement</a>} p_oElement Object
    * specifying the <code>&#60;select&#62;</code> element to be used as the data
    * source for the menu bar.
    * @param {Object} p_oConfig Optional. Object literal specifying the
    * configuration for the menu bar. See configuration class documentation for
    * more details.
    * @class Menubar
    * @constructor
    * @extends YAHOO.widget.Menu
    * @namespace YAHOO.widget
    */
    YAHOO.widget.MenuBar = function(p_oElement, p_oConfig) {

        YAHOO.widget.MenuBar.superclass.constructor.call(
                this,
                p_oElement,
                p_oConfig
            );

    };

    /**
    * Constant representing the MenuBar's configuration properties
    * @property YAHOO.widget.MenuBar._DEFAULT_CONFIG
    * @private
    * @final
    * @type Object
    */
    YAHOO.widget.MenuBar._DEFAULT_CONFIG = {

        "POSITION": {
            key: "position",
            value: "static",
            validator: YAHOO.widget.Menu._checkPosition,
            supercedes: ["visible"]
        },

        "SUBMENU_ALIGNMENT": {
            key: "submenualignment",
            value: ["tl","bl"]
        },

        "AUTO_SUBMENU_DISPLAY": {
            key: "autosubmenudisplay",
            value: false,
            validator: YAHOO.lang.isBoolean
        }

    };

    YAHOO.lang.extend(YAHOO.widget.MenuBar, YAHOO.widget.Menu, {

    /**
    * @method init
    * @description The MenuBar class's initialization method. This method is
    * automatically called by the constructor, and sets up all DOM references for
    * pre-existing markup, and creates required markup if it is not already present.
    * @param {String} p_oElement String specifying the id attribute of the
    * <code>&#60;div&#62;</code> element of the menu bar.
    * @param {String} p_oElement String specifying the id attribute of the
    * <code>&#60;select&#62;</code> element to be used as the data source for the
    * menu bar.
    * @param {<a href="http://www.w3.org/TR/2000/WD-DOM-Level-1-20000929/level-
    * one-html.html#ID-22445964">HTMLDivElement</a>} p_oElement Object specifying
    * the <code>&#60;div&#62;</code> element of the menu bar.
    * @param {<a href="http://www.w3.org/TR/2000/WD-DOM-Level-1-20000929/level-
    * one-html.html#ID-94282980">HTMLSelectElement</a>} p_oElement Object
    * specifying the <code>&#60;select&#62;</code> element to be used as the data
    * source for the menu bar.
    * @param {Object} p_oConfig Optional. Object literal specifying the
    * configuration for the menu bar. See configuration class documentation for
    * more details.
    */
    init: function(p_oElement, p_oConfig) {

        if(!this.ITEM_TYPE) {

            this.ITEM_TYPE = YAHOO.widget.MenuBarItem;

        }

        // Call the init of the superclass (YAHOO.widget.Menu)

        YAHOO.widget.MenuBar.superclass.init.call(this, p_oElement);

        this.beforeInitEvent.fire(YAHOO.widget.MenuBar);

        if(p_oConfig) {

            this.cfg.applyConfig(p_oConfig, true);

        }

        this.initEvent.fire(YAHOO.widget.MenuBar);

    },

    // Constants

    /**
    * @property CSS_CLASS_NAME
    * @description String representing the CSS class(es) to be applied to the menu
    * bar's <code>&#60;div&#62;</code> element.
    * @default "yuimenubar"
    * @final
    * @type String
    */
    CSS_CLASS_NAME: "yuimenubar",

    // Protected event handlers

    /**
    * @method _onKeyDown
    * @description "keydown" Custom Event handler for the menu bar.
    * @private
    * @param {String} p_sType String representing the name of the event that
    * was fired.
    * @param {Array} p_aArgs Array of arguments sent when the event was fired.
    * @param {YAHOO.widget.MenuBar} p_oMenuBar Object representing the menu bar
    * that fired the event.
    */
    _onKeyDown: function(p_sType, p_aArgs, p_oMenuBar) {

        var Event = YAHOO.util.Event,
            oEvent = p_aArgs[0],
            oItem = p_aArgs[1],
            oSubmenu;

        if(oItem && !oItem.cfg.getProperty("disabled")) {

            var oItemCfg = oItem.cfg;

            switch(oEvent.keyCode) {

                case 37:    // Left arrow
                case 39:    // Right arrow

                    if(
                        oItem == this.activeItem &&
                        !oItemCfg.getProperty("selected")
                    ) {

                        oItemCfg.setProperty("selected", true);

                    }
                    else {

                        var oNextItem = (oEvent.keyCode == 37) ?
                                oItem.getPreviousEnabledSibling() :
                                oItem.getNextEnabledSibling();

                        if(oNextItem) {

                            this.clearActiveItem();

                            oNextItem.cfg.setProperty("selected", true);

                            if(this.cfg.getProperty("autosubmenudisplay")) {

                                oSubmenu = oNextItem.cfg.getProperty("submenu");

                                if(oSubmenu) {

                                    oSubmenu.show();

                                }

                            }

                            oNextItem.focus();

                        }

                    }

                    Event.preventDefault(oEvent);

                break;

                case 40:    // Down arrow

                    if(this.activeItem != oItem) {

                        this.clearActiveItem();

                        oItemCfg.setProperty("selected", true);
                        oItem.focus();

                    }

                    oSubmenu = oItemCfg.getProperty("submenu");

                    if(oSubmenu) {

                        if(oSubmenu.cfg.getProperty("visible")) {

                            oSubmenu.setInitialSelection();
                            oSubmenu.setInitialFocus();

                        }
                        else {

                            oSubmenu.show();

                        }

                    }

                    Event.preventDefault(oEvent);

                break;

            }

        }

        if(oEvent.keyCode == 27 && this.activeItem) { // Esc key

            oSubmenu = this.activeItem.cfg.getProperty("submenu");

            if(oSubmenu && oSubmenu.cfg.getProperty("visible")) {

                oSubmenu.hide();
                this.activeItem.focus();

            }
            else {

                this.activeItem.cfg.setProperty("selected", false);
                this.activeItem.blur();

            }

            Event.preventDefault(oEvent);

        }

    },

    /**
    * @method _onClick
    * @description "click" event handler for the menu bar.
    * @protected
    * @param {String} p_sType String representing the name of the event that
    * was fired.
    * @param {Array} p_aArgs Array of arguments sent when the event was fired.
    * @param {YAHOO.widget.MenuBar} p_oMenuBar Object representing the menu bar
    * that fired the event.
    */
    _onClick: function(p_sType, p_aArgs, p_oMenuBar) {

        YAHOO.widget.MenuBar.superclass._onClick.call(
            this,
            p_sType,
            p_aArgs,
            p_oMenuBar
        );

        var oItem = p_aArgs[1];

        if(oItem && !oItem.cfg.getProperty("disabled")) {

             var Event = YAHOO.util.Event,
                 Dom = YAHOO.util.Dom,

                 oEvent = p_aArgs[0],
                 oTarget = Event.getTarget(oEvent),

                 oActiveItem = this.activeItem,
                 oConfig = this.cfg;

            // Hide any other submenus that might be visible

            if(oActiveItem && oActiveItem != oItem) {

                this.clearActiveItem();

            }

            oItem.cfg.setProperty("selected", true);

            // Show the submenu for the item

            var oSubmenu = oItem.cfg.getProperty("submenu");

            if(oSubmenu && oTarget != oItem.submenuIndicator) {

                if(oSubmenu.cfg.getProperty("visible")) {

                    oSubmenu.hide();

                }
                else {

                    oSubmenu.show();

                }

            }

        }

    },

    // Public methods

    /**
    * @method toString
    * @description Returns a string representing the menu bar.
    * @return {String}
    */
    toString: function() {

        var sReturnVal = "MenuBar",
            sId = this.id;

        if(sId) {

            sReturnVal += (" " + sId);

        }

        return sReturnVal;

    },

    /**
    * @description Initializes the class's configurable properties which can be
    * changed using the menu bar's Config object ("cfg").
    * @method initDefaultConfig
    */
    initDefaultConfig: function() {

        YAHOO.widget.MenuBar.superclass.initDefaultConfig.call(this);

        var oConfig = this.cfg,
            DEFAULT_CONFIG = YAHOO.widget.MenuBar._DEFAULT_CONFIG;

    	// Add configuration properties

        /*
            Set the default value for the "position" configuration property
            to "static" by re-adding the property.
        */

        /**
        * @config position
        * @description String indicating how a menu bar should be positioned on the
        * screen.  Possible values are "static" and "dynamic."  Static menu bars
        * are visible by default and reside in the normal flow of the document
        * (CSS position: static).  Dynamic menu bars are hidden by default, reside
        * out of the normal flow of the document (CSS position: absolute), and can
        * overlay other elements on the screen.
        * @default static
        * @type String
        */
        oConfig.addProperty(
            DEFAULT_CONFIG.POSITION.key,
            {
                handler: this.configPosition,
                value: DEFAULT_CONFIG.POSITION.value,
                validator: DEFAULT_CONFIG.POSITION.validator,
                supercedes: DEFAULT_CONFIG.POSITION.supercedes
            }
        );

        /*
            Set the default value for the "submenualignment" configuration property
            to ["tl","bl"] by re-adding the property.
        */

        /**
        * @config submenualignment
        * @description Array defining how submenus should be aligned to their
        * parent menu bar item. The format is: [itemCorner, submenuCorner].
        * @default ["tl","bl"]
        * @type Array
        */
        oConfig.addProperty(
            DEFAULT_CONFIG.SUBMENU_ALIGNMENT.key,
            {
                value: DEFAULT_CONFIG.SUBMENU_ALIGNMENT.value
            }
        );

        /*
            Change the default value for the "autosubmenudisplay" configuration
            property to "false" by re-adding the property.
        */

        /**
        * @config autosubmenudisplay
        * @description Boolean indicating if submenus are automatically made
        * visible when the user mouses over the menu bar's items.
        * @default false
        * @type Boolean
        */
    	oConfig.addProperty(
    	   DEFAULT_CONFIG.AUTO_SUBMENU_DISPLAY.key,
    	   {
    	       value: DEFAULT_CONFIG.AUTO_SUBMENU_DISPLAY.value,
    	       validator: DEFAULT_CONFIG.AUTO_SUBMENU_DISPLAY.validator
           }
        );

    }

    }); // END YAHOO.lang.extend

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