function change_on(imgName) {
var name;
imgOn=new Image();
imgOn.src="on.gif";
	imgOn=eval("imgOn.src");
	name=eval("document.img"+imgName);
	name.src=imgOn;
}


function change_off(imgName) {
var name;
imgOff=new Image();
imgOff.src="off.gif";
	imgOff=eval("imgOff.src");
	name=eval("document.img"+imgName);
	name.src=imgOff;
}