EN.registerModule("tabNav", {
        onDomReady:function() {                           
                var links = document.getElementById("letter-nav").getElementsByTagName('a');                              
                for(var i = 0, lnk; lnk = links[i]; i++) {
                        lnk.onclick = function(e) {                                
                                var links = document.getElementById("letter-nav").getElementsByTagName('a'),
                                    ul;                                
                                for(var i = 0, lnk; lnk = links[i]; i++) {
                                        lnk.className = lnk.className.replace(/ui-tab-active/, '');
                                        ul = document.getElementById(lnk.href.substring(lnk.href.indexOf('#')+1));
                                        ul.style.display = "none";
                                };                               
                                ul = document.getElementById(this.href.substring(this.href.indexOf('#')+1));
                                ul.style.display = "block";                                
                                this.className += " ui-tab-active";  
                                return false;     
                        };
                };
        }
});