ExtJs 4给菜单和按钮加上快捷键

Ext.ux.ToolbarKeyMap = Ext.extend(Object, (function() {
    var kb,
        owner,
        mappings;
 
    function addKeyBinding(c) {
        if (kb = c.keyBinding) {
            delete c.keyBinding;
            if (!kb.fn && c.handler) {
                kb.fn = function(k, e) {
                    e.preventDefault();
                    e.stopEvent();
                    c.handler.call(c.scope, c, e);
                }
            }
            mappings.push(kb);
            var t = [];
            if (kb.ctrl) t.push('Ctrl');
            if (kb.alt) t.push('Alt');
            if (kb.shift) t.push('Shift');
            t.push(kb.key.toUpperCase());
            c.hotKey = t.join('+');
            c.showHotKey = kb.showHotKey;
            if (c instanceof Ext.menu.Item) {
                c.onRender = Ext.Function.createSequence(c.onRender,addMenuItemHotKey);
            } else if ((c instanceof Ext.Button) && (c.showHotKey)) {
                c.onRender = Ext.Function.createSequence(c.onRender,addButtonHotKey);
            }
        }
        if ((c instanceof Ext.Button) && c.menu) {
            c.menu.cascade(addKeyBinding);
        }
    }
 
    function findKeyNavs() {
        delete this.onRender;
        if (owner = this.ownerCt) {
            mappings = [];
            this.cascade(addKeyBinding);
            if (!owner.menuKeyMap) {
                //owner.menuKeyMap = new Ext.KeyMap(owner.el, mappings);
                var target = document;
                if((mappings[0].global!=null)&&(mappings[0].global==false))
                {
                    target=owner.el;
                }
                owner.menuKeyMap = new Ext.KeyMap(target, mappings);
                owner.el.dom.tabIndex = 0;
            } else {
                owner.menuKeyMap.addBinding(mappings);
            }
        }
    }
 
    function addMenuItemHotKey() {
        delete this.onRender;
        if((this.showHotKey!=null)&&(this.showHotKey == false))
           return;
 
        this.el.child('.x-menu-item-link').setStyle({
            overflow: 'hidden',
            zoom: 1
        });
 
        this.el.child('.x-menu-item-link').child('.x-menu-item-text').setStyle({
                  'float': 'left'
                  });
 
        this.el.child('.x-menu-item-link').createChild({
            style: {
                padding: '0px 0px 0px 15px',
                float: 'right',
            },
            html: this.hotKey
        });
    }
 
    function addButtonHotKey() {
        delete this.onRender;
        if((this.showHotKey!=null)&&(this.showHotKey == false))
           return;
        var p = this.btnEl.up('');
        p.setStyle({
            overflow: 'hidden',
            zoom: 1
        });
        if(p.up('td')!=null)
           p.up('td').setStyle('text-align', 'left');
        this.btnEl.setStyle('.x-menu-item-text').setStyle({
            'float': 'left'
        });
        p = p.createChild({
                style: {
                padding: '0px 0px 0px 15px',
                float: 'right',
                position: 'relative',
                bottom: Ext.isWebKit ? '-1px' : '-2px'
            },
            html: this.hotKey
        });
    }
 
    return {
        init: function(toolbar) {
             toolbar.onRender = Ext.Function.createSequence(toolbar.onRender,findKeyNavs);
            toolbar.doLayout = Ext.Function.createSequence(toolbar.doLayout,findKeyNavs);
 
        }
    }
})());

tbar: {
            plugins: new Ext.ux.ToolbarKeyMap(),
            items: [{
                text: 'Main Menu',
                menu: {
                    items: [{
                        text: 'First option',
                        keyBinding: {
                            key: 'a',
                            ctrl: true
                        },
                        handler: onMenuClick
                    }, {
                        text: 'Second option',
                        keyBinding: {
                            key: 'c',
                            alt: true
                        },
                        handler: onMenuClick
                    }]
                }
            }, {
                text: 'A Button',
                handler: function() {
                    alert("Clicked button");
                },
                keyBinding: {
                    key: 'd',
                    ctrl: true,
                    alt: true
                },
                showHotKey: true // defaults to NOT showing the hotkey name
            }]
        },