TAB_HEADINGS = 'h2';

TAB_CLASS = 'tab';

SECTION_CLASS = 'section';

QUERY_SECTION_ARG = 'section';

TAB_SELECTED_CLASS = 'selected';

TAB_NOT_SELECTED_CLASS = 'not-selected';

LOADING_ELM_ID = 'loading';


CONTENT_HOLDER_ID = 'content-holder';

lastSection = 0 

function checkHash(){

var section = get_selected();

if (section != lastSection) {

show_section(section);

lastSection = section;


} 


} 

function get_elements(){


var divs = document.getElementsByTagName("div");

var htags = document.getElementsByTagName(TAB_HEADINGS);

sections = [];

tabs = [];

headings = [] 

for (var i = 0;

i < divs.length;

i++) {

if (divs[i].className == SECTION_CLASS)  

sections.push(divs[i]);


} 

for (var i = 0;

i < htags.length;

i++) {

if (htags[i].className == TAB_CLASS) {

var span = document.createElement("span");

span.innerHTML = htags[i].innerHTML;

tabs.push(span);


headings.push(htags[i]);


} 


} 


} ;

function combine_tabs(){

if (headings.length == 0)  

return;

headings[0].innerHTML = '';

for (var i = 0;

i < tabs.length;

i++) {

//    headings[i].removeChild(tabs[i]); 

headings[0].appendChild(tabs[i]);

if (i > 0)  

headings[i].parentNode.removeChild(headings[i]);


} 


} ;

function hide_all(){

for (var i = 0;

i < sections.length;

i++) {

sections[i].style.display = "none";



} 

for (var i = 0;

i < tabs.length;

i++) {

tabs[i].className = TAB_NOT_SELECTED_CLASS 


} 


} ;

function show_section(index){

hide_all() 

if (sections.length == 0)  

return;

var section = sections[index];


if (!section)  

var section = sections[index = 0];

section.style.display = "block";

tabs[index].className = TAB_SELECTED_CLASS;

var id = headings[index].getAttribute('id') || sections[index].getAttribute('id');


if (id && index != lastSection) {

var y = typeof window.pageYOffset != 'undefined' ? window.pageYOffset : document.documentElement.scrollTop;

location.hash = '#' + id;

window.scrollTo(0, y);

if (typeof load_tab == 'function')  

load_tab(id);


} 

lastSection = index;


} ;

function tab_click(e){

var target = e && e.target || event.srcElement;

for (var i = 0;

i < tabs.length;

i++) {

if (target == tabs[i] || target.parentNode == tabs[i]) {


show_section(i);


} 


} 


} ;

function set_handlers(){

for (var i = 0;

i < tabs.length;

i++) {

tabs[i].onclick = tab_click;


} 


} ;

function get_selected(){

var selected = 0;

if (location.hash) {

selected = location.hash.substring(1);



} 

else  

if (location.search) {

var args = location.search.substring(1).split('&');

for (var i = 0;

i < args.length;

i++) {

var name = args[i].split('=')[0];

var value = args[i].split('=')[1];

if (name == QUERY_SECTION_ARG) {


selected = value;

break;


} 


} 


} 

if (isNaN(selected)) {

for (var i = 0;

i < sections.length;

i++) {

if (sections[i].getAttribute('id') == selected || headings[i].getAttribute('id') == selected) {


selected = i;

break;


} 


} 


} 

return selected;


} ;

function set_up(){

get_elements();

combine_tabs();

var loadingElm = document.getElementById(LOADING_ELM_ID);

if (loadingElm) {

loadingElm.style.display = "none";



} 

var contentHolderElm = document.getElementById(CONTENT_HOLDER_ID);

if (contentHolderElm) {

contentHolderElm.style.display = "block";


} 

var selected = get_selected();

show_section(selected);

set_handlers();


setInterval(checkHash, 100);


} ;

onload = set_up