function findPos(obj) {
  var curleft = curtop = 0;
  if (obj.offsetParent) {
    do {
      curleft += obj.offsetLeft;
      curtop += obj.offsetTop;
    } while (obj = obj.offsetParent);
  }
  return [curleft,curtop];
}

// home page
var current_banner;
var bannerTimer;
function swap_banner(n) {
  if (n == null) {
    if (current_banner == null) current_banner = Math.floor(Math.random() * banners.length);
    n = current_banner;
    current_banner++; 
    if (current_banner >= banners.length) current_banner = 0;
  } else clearInterval(bannerTimer);
  $('div.home_banner_link').css('display','none');
  $('div#home_banner_link'+n).css('display','block');
  $('div#home_banner').css('background-image','url('+banners[n]+')');
}

// teras page
function teras_guide(guide) {
  $('div.teras_guide_link').css('background-color','');
  $('div.teras_article').hide();
  $('div#teras_button_'+guide).css('background-color','#ddd');
  $('div#teras_brief_'+guide).show();
}

// image popup
function gallery(img,str) {
  var s = ""; 
  if (str != null && str != "") s = '<div style="margin: 5px;">'+str+'</div>';
  $("div#gallery_handle").html('') // first remove contents
    .append('<div class="gallery"><img src="'+img+'"/><br>'+s+'</div>') // create image
    .find('img').click(function(){ // make image click remove popup
      $("div#gallery_handle").html(''); // clear contents
    });
}

$(document).ready(function(){
  // ie7 hack workaround z-index bug, re-index all divs
  zi = 2000;
  cn = document.getElementsByTagName('div');
  for (n=0;n<cn.length;n++){
    cn[n].style.zIndex=zi--;
  }
  // setup navigation menus
  $('.nav_main').hover(
  	function() { 
      $(this).css({'background-image':'url("i/submenu_bg.gif")','color': 'white'});
      $('div.nav_hover', this).css('visibility','visible'); 
    },
  	function() { 
      $(this).css({'background-image':'','color':'white'});
      $('div.nav_hover', this).css('visibility','hidden'); 
    }
  );
  $('.nav_link').hover(
    function(){ 
      $(this).css({'color':'#1b3e69','text-decoration':'underline'})
    },
    function(){ 
      $(this).css({'color':'','text-decoration':''})
    }
  );
});