// addEvent
function addEvent(obj, type, fn) {
  //info('addEvent(' + typeof(obj) + ', ' + typeof(type) + ', ' + typeof(fn) + ')');

  if (obj.addEventListener) {
    obj.addEventListener(type, fn, false);
    return true;
  } else if (obj.attachEvent) {
    var s   = 'e' + type + fn;
    obj[s]  = fn;
    obj[type + fn] = function() { obj[s](window.event); }
    return obj.attachEvent('on' + type, obj[type + fn]);
  }

  return false;
} // addEvent

// removeEvent
function removeEvent(obj, type, fn) {
  //info('removeEvent(' + typeof(obj) + ', ' + typeof(type) + ', ' + typeof(fn) + ')');

  if (obj.removeEventListener) {
    obj.removeEventListener(type, fn, false);
    return true;
  } else if (obj.detachEvent) {
    var r = obj.detachEvent('on' + type, obj[type + fn]);
    obj[type + fn]        = null;
    obj['e' + type + fn]  = null;
    return r;
  }
} // removeEvent

// PRINT

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

function print_preview() {
  // Switch the stylesheet
  setActiveStyleSheet('Utskriftsvennlig versjon');
  
  // Create preview message
  add_preview_message();

  // Print the page
  window.print();
}

function add_preview_message(){
var main_content = document.getElementById('content');
var main_body = main_content.parentNode;

  if (document.getElementById){
    
    var preview_message = document.createElement('div');
    preview_message.id = 'preview-message';
  
    // Create Heading
    var preview_header = document.createElement('p');
    var preview_header_text = document.createTextNode('Dette er en utskriftsvennlig versjon. Siden vil skrives ut uten denne teksten og knappen. Trykk på knappen for å vise siden i vanlig modus igjen.');
    preview_header.appendChild(preview_header_text);
    
    // Create paragraph
    var preview_para = document.createElement('strong');
    // var preview_para_text = document.createTextNode('');
    
    var cancel_function_link = document.createElement('a');
      cancel_function_link.onclick = function(){ cancel_print_preview(); return false; };
      cancel_function_link.setAttribute('href', '#'); 
    var cancel_function_link_text = document.createTextNode('Tilbake');
    cancel_function_link.appendChild(cancel_function_link_text);
    // preview_para.appendChild(preview_para_text);
    preview_para.appendChild(cancel_function_link);
    
    // Put it all toegether
    preview_message.appendChild(preview_header); 
    preview_message.appendChild(preview_para);
    main_body.insertBefore(preview_message, main_content);

  }
}

function cancel_print_preview() {
  // Destroy the preview message
  var print_preview = document.getElementById('preview-message');
  var main_body = print_preview.parentNode;
  main_body.removeChild(print_preview);
  
  // Switch back stylesheet
  setActiveStyleSheet('Standard');
}

function setActiveStyleSheet(title) {
   var i, a, main;
   for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
     if(a.getAttribute("rel").indexOf("style") != -1
        && a.getAttribute("title")) {
       a.disabled = true;
       if(a.getAttribute("title") == title) a.disabled = false;
     }
   }
}