function installSC() {
  var params = {
  // For now, redirect users to Mozilla so we can count downloads.
    URL:'http://crypto.stanford.edu/SafeCache/stanford-safecache-0.9.xpi?rand'.replace('rand',Math.random()),
  //  URL: 'http://releases.mozilla.org/pub/mozilla.org/extensions/safecache/safecache-0.9-fx.xpi',
    IconURL: "http://crypto.stanford.edu/SafeCache/stanford-safecache.png",
    toString: function() { return this.URL; }
  }
  try {
    InstallTrigger.install({ 'SafeCache': params });
    var img = new Image();
//    img.src = "https://addons.mozilla.org/install.php?uri="+params.URL;
  } catch(e) { alert("Could not install SafeCache.\n\nYou must be using Firefox to install this extension."); }
}
function installSH() {
  var params = {
  // For now, redirect users to Mozilla so we can count downloads.
    URL:'http://crypto.stanford.edu/SafeHistory/stanford-safehistory-0.9.xpi?rand'.replace('rand',Math.random()),
  //  URL: 'http://releases.mozilla.org/pub/mozilla.org/extensions/safehistory/safehistory-0.9-fx.xpi',
    IconURL: "http://crypto.stanford.edu/SafeHistory/stanford-safehistory.png",
    toString: function() { return this.URL; }
  }
  try {
    InstallTrigger.install({ 'SafeHistory': params });
    var img = new Image();
    img.src = "https://addons.mozilla.org/install.php?uri="+params.URL;
  } catch(e) { alert("Could not install SafeHistory.\n\nYou must be using Firefox to install this extension."); }
}