function return_intervalo(producto){
	if(producto == 0 ) intervalo = 0;
	if(producto <= 100 ) intervalo = 1;
	if(producto > 100 && producto < 200 ) intervalo = 2;
	if(producto >= 200 && producto < 300 ) intervalo = 3;
	if(producto >= 300 && producto < 400 ) intervalo = 4;
	if(producto >= 400 && producto < 500 ) intervalo = 5;
	if(producto >= 500 && producto < 600 ) intervalo = 6;
	if(producto >= 600 && producto < 700 ) intervalo = 7;
	if(producto >= 700 && producto < 800 ) intervalo = 8;
	if(producto >= 800 && producto < 900 ) intervalo = 9;
	if(producto >= 800 ) intervalo = 10;

	return intervalo;
}
var precios_base = new Array(0,1.8,1.8,1.8,2.75,1.75,2.5)


var precios_portada_agendas = new Array(0,2.2,2.2,1.1,1.05,0.9,0.8,0.6,0.55,0.50,0.45,0.35);
var precios_sustitucion_agendas = new Array(0,4.4,4.4,2.3,1.5,1.2,1,0.85,0.75,0.7,0.7);
var precios_adiccion_agendas = new Array(0,2.7,2.7,1.4,0.95,0.75,0.6,0.5,0.45,0.40,0.4);
var precios_adiccion8_agendas = new Array(0,1.35,1.35,0.75,0.55,0.45,0.40,0.35,0.30,0.25,0.20);
var precios_espiral_agendas = new Array(0,0.85,0.85,0.85,0.85,0.85,0.85,0.85,0.85,0.85,0.85);

var precios_portada_infantil = new Array(0,2.53,2.53,1.27,1.21,1.04,1.04,1.04,1.04,1.04,1.04,1.04);
var precios_sustitucion_infantil = new Array(0,5.06,5.06,2.65,1.73,1.38,1.38,1.38,1.38,1.38,1.38);
var precios_adiccion_infantil = new Array(0,3.11,3.11,1.61,1.09,0.86,0.86,0.86,0.86,0.86,0.86);
var precios_adiccion8_infantil = new Array(0,1.55,0.86,0.63,0.52,0.52,0.52,0.52,0.52,0.52,0.52);
var precios_espiral_infantil = new Array(0,0.85,0.85,0.85,0.85,0.85,0.85,0.85,0.85,0.85,0.85);

function calcular(){
	var error = '';
	if($('producto').value==0){
		error += "Debe seleccionar un producto\n";	
	}
	if($('cantidad').value==0 || $('cantidad').value==''){
		error += "Debe aņadir una cantidad\n";	
	}
	if(error){
		alert(error);
	}
	else {
		if($('producto').value==1 || $('producto').value==2 || $('producto').value==3) {
			var intervalo = return_intervalo($('cantidad').value);
			var price = precios_base[$('producto').value];
			if($('portada').checked) price += precios_portada_agendas[intervalo];
			if($('sustitucion').checked) price += precios_sustitucion_agendas[intervalo];
			if($('add-16').checked) price += precios_adiccion_agendas[intervalo];
			if($('add-8').checked) price += precios_adiccion8_agendas[intervalo];
			if($('espiral').checked) price += precios_espiral_agendas[intervalo];
		}
		else {
			var intervalo = return_intervalo($('cantidad').value);
			var price = precios_base[$('producto').value];
			if($('portada').checked) price += precios_portada_infantil[intervalo];
			if($('sustitucion').checked) price += precios_sustitucion_infantil[intervalo];
			if($('add-16').checked) price += precios_adiccion_infantil[intervalo];
			if($('add-8').checked) price += precios_adiccion8_infantil[intervalo];
			if($('espiral').checked) price += precios_espiral_infantil[intervalo];
		}
		price = price*$('cantidad').value;
		$('total').innerHTML = price.toFixed(2)+'&euro;';
	}
}