var messageId = 1;

function AddMessage () {
  var inputLine = document.getElementById('inputLine');
  var output = document.getElementById('Output');

  var newLine = document.createElement("p");
  var text    = document.createTextNode(messageId + ": " + inputLine.value);

  newLine.setAttribute("class",     "chatOutputLine");  // for Firefox
  newLine.setAttribute("className", "chatOutputLine"); // for IE

  newLine.appendChild(text); 
  output.appendChild(newLine);

  alert('Printed: ' + inputLine.value);

  inputLine.focus();
  inputLine.value = '';

  messageId++;
  return false;
} // AddMessage