var tab = {
  init: function(){
    var tabs = this.setup.tabs;
    var pages = this.setup.pages;
     
    for(i=0; i<pages.length; i++) {
      if(i !== 0) pages[i].style.display = 'none';
      tabs[i].onclick = function(){ tab.showpage(this); return false; };
    }
  },
   
  showpage: function(obj){
    var tabs = this.setup.tabs;
    var pages = this.setup.pages;
    var num;
     
    for(num=0; num<tabs.length; num++) {
      if(tabs[num] === obj) break;
    }
     
    for(var i=0; i<pages.length; i++) {
      if(i == num) {
        pages[num].style.display = 'block';
        tabs[num].className = 'present';
      }
      else{
        pages[i].style.display = 'none';
        tabs[i].className = null;
      }
    }
  }
}