var old_img_id = "";
var clicked_img_id = "";
var clicked_img_file;
var clicked_imgM_file;

function show_img(img_id, img_file, event) {

  document.getElementById(img_id).style.cursor = (event == "over" ? 'pointer' : 'default');

  if ((event == 'out' && img_id != clicked_img_id) || event == 'over') {
    document.getElementById(img_id).src = img_file;	
    old_img_id = img_id;
  }
}

function click_img(img_id, imgM_file) {

  var t = new Date();
  var t_ex = t.getTime() + (60 * 60 * 1000);    // expires after 60 minutes
  t.setTime(t_ex);

  // alert("imgM_file: " + imgM_file);

  document.cookie = "img_id=" + img_id + "; expires=" + t.toGMTString();
  document.cookie = "img_file=" + imgM_file + "; expires=" + t.toGMTString();

}

function delete_cookie() {

  var t = new Date();
  document.cookie = "img_id=; expires=" + t.getTime();
  document.cookie = "img_file=; expires=" + t.getTime();
}

function read_cookie() {

  var id = "";
  var file = "";

  if (navigator.cookieEnabled) {
    if (document.cookie) {
  
      var cookies = document.cookie.split(";")
      var i = 0;
      while (i < cookies.length) {
        if (cookies[i].indexOf("img_id") != -1) {
	  var ids = cookies[i].split("=");
	  id = ids[1];
  	}
        else if (cookies[i].indexOf("img_file") != -1) {
	  var files = cookies[i].split("=");
	  file = files[1];
	}
	i++;
      }

      if (id != "" && file != "") {
	document.getElementById(id).src = file;
	clicked_img_id = id;
	//alert(file + "  " + id); 
      }
    }
  }
}