In order to control Safari or Chrome you may need to Allow JavaScript from Apple Events. Otherwise the various browser actions may fail.

In Safari, you must first enable the Develop menu by choosing Preferences from the Safari menu, changing to the Advanced panel, and enabling “Show Develop menu in menu bar”, and then choosing Allow JavaScript from Apple Events from the Develop. You can then turn off the Develop menu if desired.

In Chrome, you must choose Allow JavaScript from Apple Events from the Developer sub-menu in the View menu.