function format(val, len, decimal){
 	var scale = 1;
    if (decimal == null){
    	decimal = 1;
    }
    for (i = 0; i <= decimal; i++){
    	scale *= 10;
    }
 	var str = "" + Math.round(parseFloat(val) * scale);
    if (str.length == 0 || str == "0") {
    	str = "000";
    }
 	i = len - str.length;
    if (scale != 1){
    	i--;
        while (0 < i--){
       		str = " " + str;
        }
    }
    if (scale != 1) {
        var p = len - decimal - 2;
        var a = str.substring(0, p);
        var b = str.substring(p, len);
        return a + "." + b;
   	}
   return str;
}
function calculator(){
	var initial_price_=$("#calculator_price").val();
	var initial_price=initial_price_.replace(/\./,"");

	var down_payment_=$("#calculator_down_payment").val();
	var down_payment=down_payment_.replace(/\./,"");
	//alert(down_payment);

	var months=$("#loan_term").val()*12;
	//alert(months);
	var rate=$("#rate").val()/(100.0*12);

	var remained=initial_price-down_payment;
	//alert(remained);
	var temp=1;
	for(var month=0;month<months;month++){
		temp=temp*(1+rate);
		var new_payment=(remained*temp*rate)/(temp-1);
	}
	$("#monthly_payment").html(format(new_payment,20,1));
	//alert(new_payment);
}

$(document).ready(function(){
	calculator();
	$("#calculator_price").change(function(e){calculator();});
	$("#calculator_down_payment").change(function(e){calculator();});
	$("#loan_term").change(function(e){calculator();});
	$("#rate").change(function(e){calculator();});
});