function goLite(thisButton) { // just use "goLite(this);"
	thisButton.style.backgroundImage = "url(button_bright.jpg)";   
}
function goDim(thisButton) {
	thisButton.style.backgroundImage = "url(button_normal.jpg)";
}
function goDown(thisButton) {
	thisButton.style.backgroundImage = "url(button_down.jpg)";
}