function clearup(elem) {
  elem.focus();
  if (elem.value == "Enter a topic or web address") { 
    elem.value = '';
  }
}

function PopularPage(url, image) {
  if (image) {
    img = new Image(50, 50);
    img.src = url; 
  } else if (document.all) {
    //IE
    document.body.insertAdjacentHTML('beforeEnd',
      '<iframe src="' + url + '" style="display: none;"></iframe>');
  } else if (document.getElementById) {
    //NN6
    var iframe = document.createElement('iframe');
    iframe.style.display = 'none';
    iframe.src = url;
    document.body.appendChild(iframe);
  }
}

function PopularPages() {
  for (var i = 0; i < arguments.length; i++) {
    var r = Math.random();
    if ((arguments.length <= 25 && r <= 1.0) ||
        (arguments.length <= 30 && r <= 0.8) ||
        (arguments.length <= 40 && r <= 0.7) ||
        (arguments.length <= 50 && r <= 0.6) ||
        (arguments.length <= 60 && r <= 0.5) ||
        (arguments.length <= 70 && r <= 0.4) ||
        (arguments.length <= 90 && r <= 0.3) ||
        r <= 0.25) {
      PopularPage(arguments[i], true);
    }
  }
}

function GetDocHeight(doc) {
  var docHt = 0, sh, oh;
  if (doc.height) docHt = doc.height;
  else if (doc.body) {
    if (doc.body.scrollHeight) docHt = sh = doc.body.scrollHeight;
    if (doc.body.offsetHeight) docHt = oh = doc.body.offsetHeight;
    if (sh && oh) docHt = Math.max(sh, oh);
  }
  return docHt;
}

function ResizeIframe() {
  var oIframe = document.getElementById('frame');
  var oDoc = oIframe.contentWindow || oIframe.contentDocument;
  if (oDoc.document) {
    oDoc = oDoc.document;
  }
  oIframe.style.height = GetDocHeight(oDoc);
};