function filter(s) {
  s = s.replace(/\W+/g, ' ');
  s = s.replace(/\s+/g, ' ');
  s = s.replace(/^\s*/, '').replace(/\s*$/, '');
  if (s.length > 0) s = ' ' + s;
  return s;
}

function scrape_node(node, limit) {
  if (node.nodeType == 3) return filter(node.nodeValue);
  if (node.nodeType != 1) return "";
  if (node.nodeName == 'SCRIPT'
   || node.nodeName == 'NOSCRIPT'
   || node.nodeName == 'IMG'
   || node.nodeName == 'IFRAME' 
   || node.nodeName == 'FRAME'
   || node.nodeName == 'A'
   || node.nodeName == 'FORM' 
   || node.nodeName == 'OPTION' 
   || node.nodeName == 'STYLE')  return "";
  var result = "";
  for (var child = node.firstChild; limit - result.length > 0 && child != null;
       child = child.nextSibling) {
    result += scrape_node(child, limit - result.length);
  }
  return result;
}

function scrape_tags(tagname, limit) {
  var tags = document.getElementsByTagName(tagname);
  var result = "";
  for (var i = 0; limit - result.length > 0 && i < tags.length; i++) {
    result += scrape_node(tags[i], limit - result.length);
  }
  return result;
}

var google_old_onload = window.onload;

function google_ad() {
  var iframe = document.getElementById("google_ads_content_frame");
  if (iframe != null) {

    var url = google_ad_url + '&contents=';

    var MAXURL = 1000;
    var limit = (MAXURL - url.length)/2;

    var content = '';

    content += scrape_tags('H1',     limit - content.length);
    content += scrape_tags('H2',     limit - content.length);
    content += scrape_tags('H3',     limit - content.length);
    content += scrape_tags('H4',     limit - content.length);
    content += scrape_tags('H5',     limit - content.length);
    content += scrape_tags('H6',     limit - content.length);
    content += scrape_tags('TH',     limit - content.length);
    if (content.length > 0) {
      content = '<h1>' + content + '</h1>';
    }

    content += filter(document.title);
    limit = MAXURL - url.length - content.length;
    content += scrape_tags('BODY',   limit);

    content = escape(content).replace(/%20/g, '+');
    url += content;
    url = url.substring(0, MAXURL);
    url = url.replace(/%\w?$/, '');
    iframe.src = url;
  }

  if (google_old_onload) google_old_onload();
}

window.onload = google_ad;