Tab Mix Plus

function handleCommand(aTriggeringEvent) {
  if (aTriggeringEvent instanceof MouseEvent && aTriggeringEvent.button == 2)
    return; // Do nothing for right clicks

  var url = this.value;
  var mayInheritPrincipal = false;
  var postData = null;

  var action = this._parseActionUrl(url);
  if (action) {
    url = action.param;
    if (this.hasAttribute("actiontype")) {
      if (action.type == "switchtab") {
        this.handleRevert();
        let prevTab = gBrowser.selectedTab;
        if (switchToTabHavingURI(url) &&
            isTabEmpty(prevTab))
          gBrowser.removeTab(prevTab);
      }
      return;
    }
  }
  else {
    [url, postData, mayInheritPrincipal] = this._canonizeURL(aTriggeringEvent);
    if (!url)
      return;
  }

  this.value = url;
  gBrowser.userTypedValue = url;
  try {
    addToUrlbarHistory(url);
  } catch (ex) {
    // Things may go wrong when adding url to session history,
    // but don't let that interfere with the loading of the url.
    Cu.reportError(ex);
  }

  function loadCurrent() {
    let flags = Ci.nsIWebNavigation.LOAD_FLAGS_ALLOW_THIRD_PARTY_FIXUP;
    // Pass LOAD_FLAGS_DISALLOW_INHERIT_OWNER to prevent any loads from
    // inheriting the currently loaded document's principal, unless this
    // URL is marked as safe to inherit (e.g. came from a bookmark
    // keyword).
    if (!mayInheritPrincipal)
      flags |= Ci.nsIWebNavigation.LOAD_FLAGS_DISALLOW_INHERIT_OWNER;
    gBrowser.loadURIWithFlags(url, flags, null, null, postData);
  }

  if (aTriggeringEvent instanceof MouseEvent) {
    // We have a mouse event (from the go button), so use the standard
    // UI link behaviors
    let where = whereToOpenLink(aTriggeringEvent, false, false);
    if (where == "current") {
      loadCurrent();
    } else {
      this.handleRevert();
      content.focus();
      openUILinkIn(url, where,
                   { allowThirdPartyFixup: true, postData: postData });
    }
    return;
  }

  if (aTriggeringEvent &&
      aTriggeringEvent.altKey &&
      !isTabEmpty(gBrowser.selectedTab)) {
    this.handleRevert();
    content.focus();
   var currTab=gBrowser.mCurrentTab;
    var newTab = gBrowser.loadOneTab(url, {
                        postData: postData,
                        inBackground: false,
                        allowThirdPartyFixup: true
                  });
   gBrowser.moveTabTo(newTab, currTab._tPos+1);
    aTriggeringEvent.preventDefault();
    aTriggeringEvent.stopPropagation();
  } else {
    loadCurrent();
  }

  gBrowser.selectedBrowser.focus();

}

gURLBar.handleCommand_TMP = gURLBar.handleCommand; // you can skip this line
gURLBar.handleCommand = handleCommand;