function changebg()
{

	var value=storybg.style.background;
	var valid=value.indexOf('white');	// check if bg is currently black or white
	if (valid==-1)
	{
		storybg.style.color="black";	// change background of <div id=storybg>
		storybg.style.background="white";
		storybg.bgColor = 'white';
		document.getElementById("switch").innerHTML = "Switch: White on black"; // change span text
		document.cookie="switch=white";	// set cookie for smart choice
	}
	else
	{
		storybg.style.color = 'silver';
		storybg.style.background = '#201500';	// works in IE
		storybg.bgColor = '#201500';	// my attempt for firefox
		document.getElementById("switch").innerHTML = "Switch: Black on white";
		document.cookie="switch=black";
	}
	
	}