Power rope lighting with a battery

I am new to all of this...I am trying to get a 4 ft strand of rope lighting to work on a battery (alarm panel 12 volt I think) with a switch in between. When I connect the rope lights to the battery directly it lights fine. When I wire the switch, I take the two ends from the rope light and connect them to teh switch then I connect a wire from the switch to the battery. When the switch is on it works fine but when I turn the switch off it starts to burn. I really need help with thtis ASAP . I am making a halloween costume for a party tonight. Thanks.....