I have some great news to share! There is a replacement for the old Bridge Designer which no longer works on modern web browsers. The new pony in town is called the Bridge Simulator. Like before, it is freely hosted on the Johns Hopkins website, and created by Claire VerHulst.
This new Bridge Simulator is not quite as simple or easy to use as the older one, but it is more powerful and flexible.
I’ll work on a full video tutorial, but in the meantime feel free to check it out on your own.