// common.js
//
// Written by Y. Waki <2010>

// Slideshow for cover page

// preloaded images
var image1=new Image()
image1.src="image/cover.jpg"
var image2=new Image()
image2.src="image/cover2.jpg"
var image3=new Image()
image3.src="image/cover3.jpg"

var k=1; // index for foreground image
var l=1; // index for background image
var o=0; // opacity (0-50)

function slideit() { // main function (called every 8 sec)

  if (!document.images) return;
  document.getElementById('slideshow').style.background='url('+eval('image'+l+'.src')+')';
  document.getElementById('slideshow').style.backgroundPosition='center';
  document.getElementById('slideshow').style.backgroundRepeat='no-repeat';
  document.images.slide.style.opacity=0;
  document.images.slide.src=eval('image'+k+'.src');
  o=0; fade();
  l=k;
  if (k<3) k++; else k=1;
  setTimeout('slideit()',8000);
}

function fade() { // called from slideit (50 steps per fade)

  if (o<50) o++; else return;
  document.images.slide.style.opacity=o/50;
  document.images.slide.style.filter='alpha(opacity='+2*o+')';
  setTimeout('fade()',50);
}

// Show/hide toggle

function toggle_view(id) {

  element=document.getElementById(id);
  if (element.style.display=='block' || element.style.display=='')
    element.style.display='none';
  else element.style.display='block';
  return false;
}