OperaStyle_menuAccessKey.uc.js

// ==UserScript==
// @name           OperaStyle_menuAccessKey.uc.js
// @namespace      http://d.hatena.ne.jp/Griever/
// @include        main
// ==/UserScript==

var menuAccessKey = {
	HINTKEYS : new String('abcdefghijklmnopqrstuvwxyz0123456789'),
	init : function(){
		window.addEventListener('popupshown', this, false);
		window.addEventListener('unload', this, false);
	},
	uninit : function(){
		window.removeEventListener('popupshown', this, false);
		window.removeEventListener('unload', this, false);
	},
	getItems : function(elem){
		if (!/^(menu|menuitem)$/i.test(elem.localName)) return false;
		if (elem.hasAttribute("accesskey")){
			this.hintKeys = this.hintKeys.replace(elem.getAttribute("accesskey"), '');
			return false;
		}
		return true
	},
	setAccessKey : function(elem){
		if (this.hintKeys == '') return true;
		var key = elem.label.match( RegExp('[' + this.hintKeys + ']', 'i') );
		if (key){
			elem.setAttribute("accesskey", key[0]);
			this.hintKeys = this.hintKeys.replace(key[0].toLowerCase(), '');
		}else{
			elem.setAttribute("accesskey", this.hintKeys[0]);
			this.hintKeys = this.hintKeys.substr(1);
		}
	},
	handleEvent : function(event){
		if (event.type == 'unload'){
			this.uninit();
			return false;
		}
		this.hintKeys = this.HINTKEYS;
		Array.filter(event.target.children, this.getItems , this)
			.some(this.setAccessKey, this);
	},
}
menuAccessKey.init();