// choose_css.js
  // -------------
  // choose the appropriate stylesheet according to
  // the user's screen resolution

  document.write("<link rel='stylesheet' type='text/css' href='");

  if (window.screen.height <= 600) {
    //resolution is 800x600 or less
    document.write("/cs1.css'>");
  } else {
    document.write("/cs.css'>");
  }