function ratecalc(km){

	var baserate1 = 3400;
	var baserate2 = 8500;
	var baserate3 = 15000;


	if(!NumCheck(km) || km < 0){

		alert("距離は半角の整数で入力してください");
		document.ratecalcform.km.value = '';
		document.ratecalcform.rate.value = '';

		return true;
	}

	if(km >= 1 && km <= 20 ) {

		document.ratecalcform.rate.value = numSplit(baserate1);

	} else if(km >= 21 && km <= 50) {

		addkm = km - 20;
		addrate = addkm * 170;
		rate = addrate + baserate1;

		document.ratecalcform.rate.value = numSplit(rate);

	} else if(km >= 51 && km <= 100) {

		addkm = km - 50;
		addrate = addkm * 130;
		rate = addrate + baserate2;

		document.ratecalcform.rate.value = numSplit(rate);

	} else if(km >= 101) {

		addkm = km - 100;
		addrate = addkm * 90;
		rate = addrate + baserate3;

		document.ratecalcform.rate.value = numSplit(rate);

	}

}

function numSplit(ns) {

	var num = new String(ns).replace(/,/g, "");

	while(num != (num = num.replace(/^(-?\d+)(\d{3})/, "$1,$2")));
	return num;

}

function NumCheck(n){

	var i = 0;
	for (i = 0; i < n.length; i++){
		var s = n.substring(i, i + 1);
		if (s == "0"  ||  s == "1" ||  s == "2" || s == "3" || s == "4" || s == "5" || s == "6" || s == "7" || s == "8" || s == "9"){
			continue;
		}
		else{
			return false;
		}
	}
	return true;

}