//writes hello world to browser
function helloWorld(){
  document.write("hello world")
}

/**
  * writes the last modification to document
  */
function writeModificationTime(){
  document.write("<p>Last Modified:");
  if(document.lastModified){
    document.write(document.lastModified + "</p>");
  } else {
    document.write("Your browser lacks the javascript support needed.</p>");
  }
}

/**
  * queries an object for its attributes
  */
function queryForAttr(what){
  var output = '';
  for (var i in what)
      output += i+ '\n';
  document.write("<p>"+output+"</p>");
}

/**
  * writes the useragent string to document
  */
function writeUseragent(){
  document.write("<p>" + navigator.userAgent + "</p>");
}

/**
  * write doc height to document
  */
function writeDocHeight(){
  document.write("<p>"+getDocHeight()+"</p>");
}

/**
  * write doc width to document
  */
function writeDocWidth(){
  document.write("<p>"+getDocWidth()+"</p>");
}