prevdiv = "introduction";
function layer(imid) {
if (document.getElementById) {
document.getElementById(prevdiv).style.display = "none";
document.getElementById(''+prevdiv+'_nav').src = ''+prevdiv+'_of.gif';
document.getElementById(imid).style.display = "block";
document.getElementById(''+imid+'_nav').src = ''+imid+'_on.gif';
prevdiv = imid;
	}
}
function priceC(value) {
	document.price_form.pricing.value = value;	
}