// from "Head Rush Ajax" by Brett McLaughlin, p404
// http://www.headfirstlabs.com/books/hrajax/chapter01/boards/text-utils.js

function replaceText(el, text)
{
  if (el != null)
  {
    clearText(el);
    var newNode = document.createTextNode(text);
    el.appendChild(newNode);
  }
}

function clearText(el)
{
  if (el != null)
  {
    if (el.childNodes)
    {
      for (var i = 0; i < el.childNodes.length; i++)
      {
        var childNode = el.childNodes[i];
        el.removeChild(childNode);
      }
    }
  }
}

function getText(el)
{
  var text = "";
  if (el != null)
  {
    if (el.childNodes)
    {
      for (var i = 0; i < el.childNodes.length; i++)
      {
        var childNode = el.childNodes[i];
        if (childNode.nodeValue != null)
          text = text + childNode.nodeValue;
      }
    }
  }
  return text;
}