function imgOn(i){
	on = /_on/;
	
	if(!i.src.match(on)){
		i.src=i.src.replace(/(\.jpg)/,'_on.jpg');
	}

}
function imgOff(i){
	on = /_on/;
	if(i.src.match(on)){
		i.src=i.src.replace(on,'');
	}

}
function imgDown(i){
	on = /_on/;
	if(i.src.match(on)){
		i.src=i.src.replace(on,'_down');
	}

}