Can you complete a simple circuit and ignite fireworks remotely?

I'm extremely new to arduino. I originally bought my uno micro controller to find a way to remotely detonate fireworks. The initial basic model for my detonator would be this:

Following the instructions listed here(/projects/posts/how-to-led-arduino-php-proc/), I have set up a web site with an on/off switch.

The arduino would be connected, by nichrome wire, to a battery with a high voltage. The battery would be connected to the firework by nichrome wire too.

I wish, when the switch on the website is turned 'on', for the website to turn the arduino on. This would send a message to complete the electrical circuit and to detonate the fireworks.

Question 1: can an arduino be used to turn an electrical circuit on and off?
Question 2: can nichrome wire be connected to an arduino in the way illustrated above?
Question 3: how can the Processing IDE script be altered to complete the circuit instead of turning on an LED?
Question 4: is the procedure explained above possible and feasible?

Thank you very much for taking the time to answer my questions.

You won't get enough current out of a pin to heat nichrome.
You'll have to buffer it with a relay or transistor.

snicksocks:
Question 1: can an arduino be used to turn an electrical circuit on and off?

Yes, but how you do it depends on your current and voltage requirements. Relays, for example, are pretty common for driving high current/voltage circuits.

snicksocks:
Question 2: can nichrome wire be connected to an arduino in the way illustrated above?

No. You can drive a high current circuit with the Arduino, but you can't power one with it.

snicksocks:
Question 3: how can the Processing IDE script be altered to complete the circuit instead of turning on an LED?

Depends on what you use to drive the circuit.

snicksocks:
Question 4: is the procedure explained above possible and feasible?

I'm not familiar with the intricacies of firework lighting, but I'd imagine there are a great deal of safety concerns when dealing with these types of things.