function $() {
  var elements = new Array();

  for(var i = 0; i < arguments.length; i++) {
      var element = arguments[i];
      if (typeof element == 'string') element = document.getElementById(element);
      if (arguments.length == 1) return element;
      elements.push(element);
  }

  return elements;
}

if (!Array.prototype.push) {
   Array.prototype.push = function() {
		var startLength = this.length;
		for(var i = 0; i < arguments.length; i++)
            this[startLength + i] = arguments[i];
	    return this.length;
  }
}

document.getElementsByClassName = function(className) {
   var children = document.getElementsByTagName('*') || document.all;
   var elements = new Array();
  
   for(var i = 0; i < children.length; i++) {
       var child = children[i];
       var classNames = child.className.split(' ');
       for (var j = 0; j < classNames.length; j++) {
           if (classNames[j] == className) {
              elements.push(child);
              break;
           }
       }
   }
  
   return elements;
}

curr_tab = 0;

function go_tab(tabno) {
   curr_tab = parseInt(tabno);
   tab_pages = document.getElementsByClassName('tab_page');
   TabToggle(tab_pages[curr_tab]);
}

function next_tab() {
   curr_tab = curr_tab+1;
   tab_pages = document.getElementsByClassName('tab_page');
   TabToggle(tab_pages[curr_tab]);
}

function prev_tab() {
   curr_tab = curr_tab-1;
   tab_pages = document.getElementsByClassName('tab_page');
   TabToggle(tab_pages[curr_tab]);
}

TabToggle = function(element) {
   // This gives the active tab its look
   var tabs = $('tabs').getElementsByTagName('li');
   for(j = 0; j < tabs.length; j++) {
       link = tabs[j].getElementsByTagName('a')[0];
       link.id = "";
       tabs[j].id = "";
   }
   element.id = "current"
   element.parentNode.id = "active"
  
   //Hide all content containers
   contents = document.getElementsByClassName('tabset_content');
   for(var i = 0; i < contents.length; i++) {
       contents[i].style.display = 'none';
   }

   //Extract content container id from href

   tabname = element.getAttribute('href').replace(/^.*\#/,'');
   ele = $(tabname);
   ele.style.display = 'block';
   curr_tab = tabname.substring(3,4)
   curr_tab = curr_tab-1;
   tab_pages = document.getElementsByClassName('tab_page');
   // if(tab_pages[3]==null) {
   //   last_tab = 2;
   // } else {
   //   last_tab = 3;
   //}
   last_tab = tabs.length-1   
}