function changeimg(image) {
   		var imgsrc = image.src;
		var len = imgsrc.length;
		var tester = imgsrc.substr((len-7), 3);
		if(tester == "off") {
			var re = new RegExp('_off', 'gi');
			var myimage = imgsrc.replace(re, '_on');
			image.src = myimage;
		}
		else {
			var re = new RegExp('_on', 'gi');
			var myimage = imgsrc.replace(re, '_off');
			image.src = myimage;
		}
}