function bt_selected(){
	//main menu buttons
	document.getElementById("liselected").childNodes[0].style.color = "#50706F";
	document.getElementById("liselected").childNodes[0].childNodes[0].src= "library/menu_bt_selected.png";
	//left menu buttons
}

function swap(target, fname) {
		document[target].src = "library/" + fname;
}

function swapBack(target, fname) {
		document[target].src = "library/" + fname;
		document.getElementById("liselected").childNodes[0].childNodes[0].src = "library/menu_bt_selected.png";
}