var panels = ['slide0', 'slide1', 'slide2', 'slide3'];
var c = 0;

function slide(which)
{
	$('#slide' + c).hide();
	
	if (which == 'next')
	{
		c++;
		
		if (c == panels.length) {c = 0;}
	}
	else
	{
		c--;
		
		if (c < 0) {c = panels.length - 1;}
	}
	
	$('#slide' + c).show();
}

function my_submit()
{
	var f = false;
	var df = document.forms[0];
	
	for (var i = 0;i < df.p_model.length;i++)
	{
		if (df.p_model[i].checked)
		{
			id = df.p_model[i].value;
			f = true;
			break;
		}
	}
	
	if (!f)
	{
		alert('Abans cal triar una corona!');
		return;
	}
	
	if (df.c_name.value == '' || df.c_address.value == '' || df.c_city.value == '' || df.c_cif.value == '')
	{
		alert('Cal posar el nom, adreça i el NIF/CIF per poder fer la factura!');
		return;
	}
	
	df.submit();
}