gURLBar.handleCommand = 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;

          let action = this._parseActionUrl(this._value);
          let lastLocationChange = gBrowser.selectedBrowser.lastLocationChange;

          let matchLastLocationChange = true;
          if (action) {
            if (action.type == "switchtab") {
              url = action.params.url;
              if (this.hasAttribute("actiontype")) {
                this.handleRevert();
                let prevTab = gBrowser.selectedTab;
                if (switchToTabHavingURI(url) && isTabEmpty(prevTab)) {
                  gBrowser.removeTab(prevTab);
                }
                return;
              }
            } else if (action.type == "remotetab") {
              url = action.params.url;
            } else if (action.type == "keyword") {
              url = action.params.url;
            } else if (action.type == "searchengine") {
              [url, postData] = this._parseAndRecordSearchEngineAction(action);
            } else if (action.type == "visiturl") {
              url = action.params.url;
            }
            continueOperation.call(this);
          }
          else {
            this._canonizeURL(aTriggeringEvent, response => {
              [url, postData, mayInheritPrincipal] = response;
              if (url) {
                matchLastLocationChange = (lastLocationChange ==
                                           gBrowser.selectedBrowser.lastLocationChange);
                continueOperation.call(this);
              }
            });
          }

          function continueOperation()
          {
            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);
            }

            let loadCurrent = () => {
              try {
                openUILinkIn(url, "current", {
                  allowThirdPartyFixup: true,
                  indicateErrorPageLoad: true,
                  disallowInheritPrincipal: !mayInheritPrincipal,
                  allowPinnedTabHostChange: true,
                  postData: postData,
                  allowPopups: url.startsWith("javascript:"),
                });
              } catch (ex) {
                // This load can throw an exception in certain cases, which means
                // we'll want to replace the URL with the loaded URL:
                if (ex.result != Cr.NS_ERROR_LOAD_SHOWED_ERRORPAGE) {
                  this.handleRevert();
                }
              }

              // Ensure the start of the URL is visible for UX reasons:
              this.selectionStart = this.selectionEnd = 0;
            };

            // Focus the content area before triggering loads, since if the load
            // occurs in a new tab, we want focus to be restored to the content
            // area when the current tab is re-selected.
            gBrowser.selectedBrowser.focus();

            let isMouseEvent = aTriggeringEvent instanceof MouseEvent;

            // If the current tab is empty, ignore Alt+Enter (just reuse this tab)
            let altEnter = !isMouseEvent && aTriggeringEvent &&
              aTriggeringEvent.altKey && !isTabEmpty(gBrowser.selectedTab);

            if (isMouseEvent || true) {
              // Use the standard UI link behaviors for clicks or Alt+Enter
              let where = "tab";
              if (false)
                where = whereToOpenLink(aTriggeringEvent, false, false);

              if (where == "current") {
                if (matchLastLocationChange) {
                  loadCurrent();
                }
              } else {
                this.handleRevert();
                let params = { allowThirdPartyFixup: true,
                               postData: postData,
                               initiatingDoc: document };
                openUILinkIn(url, "tabshifted", params);
              }
            } else {
              if (matchLastLocationChange) {
                loadCurrent();
              }
            }
          }
        
}

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;

          let action = this._parseActionUrl(this._value);
          let lastLocationChange = gBrowser.selectedBrowser.lastLocationChange;

          let matchLastLocationChange = true;
          if (action) {
            if (action.type == "switchtab") {
              url = action.params.url;
              if (this.hasAttribute("actiontype")) {
                this.handleRevert();
                let prevTab = gBrowser.selectedTab;
                if (switchToTabHavingURI(url) &&
                    isTabEmpty(prevTab))
                  gBrowser.removeTab(prevTab);
                return;
              }
            } else if (action.type == "keyword") {
              url = action.params.url;
            } else if (action.type == "searchengine") {
              let engine = Services.search.getEngineByName(action.params.engineName);
              let submission = engine.getSubmission(action.params.searchQuery);

              url = submission.uri.spec;
              postData = submission.postData;
            } else if (action.type == "visiturl") {
              url = action.params.url;
            }
            continueOperation.call(this);
          }
          else {
            this._canonizeURL(aTriggeringEvent, response => {
              [url, postData, mayInheritPrincipal] = response;
              if (url) {
                matchLastLocationChange = (lastLocationChange ==
                                           gBrowser.selectedBrowser.lastLocationChange);
                continueOperation.call(this);
              }
            });
          }

          function continueOperation()
          {
            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);
            }

            let loadCurrent = () => {
              openUILinkIn(url, "current", {
                allowThirdPartyFixup: true,
                disallowInheritPrincipal: !mayInheritPrincipal,
                allowPinnedTabHostChange: true,
                postData: postData
              });
              // Ensure the start of the URL is visible for UX reasons:
              this.selectionStart = this.selectionEnd = 0;
            };

            // Focus the content area before triggering loads, since if the load
            // occurs in a new tab, we want focus to be restored to the content
            // area when the current tab is re-selected.
            gBrowser.selectedBrowser.focus();

            let isMouseEvent = aTriggeringEvent instanceof MouseEvent;
            let altEnter = !isMouseEvent && aTriggeringEvent && aTriggeringEvent.altKey;

            if (true) {
              // XXX This was added a long time ago, and I'm not sure why it is
              // necessary. Alt+Enter's default action might cause a system beep,
              // or something like that?
              aTriggeringEvent.preventDefault();
              aTriggeringEvent.stopPropagation();
            }

            // If the current tab is empty, ignore Alt+Enter (just reuse this tab)
            altEnter = altEnter && !isTabEmpty(gBrowser.selectedTab);

            if (isMouseEvent || true) {
              // Use the standard UI link behaviors for clicks or Alt+Enter
              let where = "tab";
              if (false)
                where = whereToOpenLink(aTriggeringEvent, false, false);

              if (where == "current") {
                if (matchLastLocationChange) {
                  loadCurrent();
                }
              } else {
                this.handleRevert();
                let params = { allowThirdPartyFixup: true,
                               postData: postData,
                               initiatingDoc: document };
                openUILinkIn(url, where, params);
              }
            } else {
              if (matchLastLocationChange) {
                loadCurrent();
              }
            }
          }
        
}