function setBack(show)
{
	if(show=='about')
		document.getElementById("middle").style.background="transparent url(images/success.png) center right no-repeat";
	else if(show=='creative')
		document.getElementById("middle").style.background="transparent url(images/guitar.jpg) center right no-repeat";
	else
		document.getElementById("middle").style.background="transparent url(images/success.png) center right no-repeat";
}