function hon( p_id, color ) {
  var handle = document.getElementById( p_id );
  handle.style.backgroundColor = color;
  }

function main_screen_turn_on( image_name, this_caption, img_offset ) {
  var img_tag  = document.getElementById( "main_screen" );
  var shader   = document.getElementById( "shade" );
  var body     = document.getElementById( "body_tag" );
  var div_tag  = document.getElementById( "image_view" );
  var cap_tag  = document.getElementById( "caption" );

  img_tag.src = "images/content/" + image_name;
  shader.style.top    = "0px";
  shader.style.left   = "0px";
  shader.style.width  = "100%";
  if( navigator.appName == "Microsoft Internet Explorer" )
    shader.style.height = body.scrollHeight + "px";
  else {
    if( body.scrollHeight > window.innerHeight ) {
      var this_height = parseInt( document.body.clientHeight ) + 36;
      shader.style.height = this_height + "px";
      }
    else shader.style.height = window.innerHeight + "px";
    }
  shader.style.visibility = "visible";
  div_tag.style.left = "240px";
  if( navigator.appName == "Microsoft Internet Explorer" ) {
    if( img_offset.substr(-2,2) == 'px' )
      div_tag.style.top = img_offset;
    else {
      var true_offset = parseInt( document.documentElement.scrollTop ) + parseInt( img_offset );
      div_tag.style.top = true_offset + 'px';
      }
    }
  else {
    if( img_offset.substr(-2,2) == 'px' )
      true_offset = img_offset;
    else
      true_offset = parseInt( window.scrollY ) + parseInt( img_offset ) + 'px';
    div_tag.style.top = true_offset;
    }
  cap_tag.innerHTML = this_caption;
  div_tag.style.visibility = "visible";
  }

function main_screen_turn_off()
  {
  var img_tag = document.getElementById( "main_screen" );
  var div_tag = document.getElementById( "image_view" );
  var cap_tag = document.getElementById( "caption" );
  var shader  = document.getElementById( "shade" );
  img_tag.src = "";
  div_tag.style.visibility = "hidden";
  div_tag.style.top = "-2000px";
  cap_tag.innerHTML = "";
  shader.style.top    = "-2000px";
  shader.style.left   = "0px";
  shader.style.width  = "0px";
  shader.style.height = "0px";
  shader.style.visibility = "hidden";
  }