function displayOn(what) {
	document.getElementById(what).style.display = 'block;';
}

function displayOff(what) {
	document.getElementById(what).style.display = 'none;';
}

function handleOn(imgName) {
	pathOld = document[imgName].src;
	pathNew = pathOld.replace(imgName, imgName + '_on');
	document[imgName].src = pathNew;
}

function handleOff(imgName) {
	pathOld = document[imgName].src;
	pathNew = pathOld.replace('_on', '');
	document[imgName].src = pathNew;
}