function round(number, place) {
	place = (!place ? 2 : place);
	return Math.round(number*Math.pow(10,place))/Math.pow(10,place);
}

function computeForm() {
	if(validateForm()) {
		var n = document.calculator.years.value*12;
		var r = document.calculator.rate.value/(12*100);
		var P = document.calculator.financed.value;
		var temp=1;
		for(var i=0; i<n; i++) {
			temp=temp*(1+r);
		}
		if (temp!=1) {
		var a = round((P*temp*r)/(temp-1),2);
		} else {
			var a = 0;
		}
		document.calculator.payment.value=a;
	} else {
		alert('Invalid Input');
	}
}

function computeForm2() {
	if(validateForm()) {
		var n = document.calculator.years.value*12;
		var r = document.calculator.rate.value/(12*100);
		var P = document.calculator.financed.value;
		var temp=1;
		for(var i=0; i<n; i++) {
			temp=temp*(1+r);
		}
		if (temp!=1) {
			var a = round((P*temp*r)/(temp-1),2);
		} else {
			var a = 0;
		}
		getObj('payment').innerHTML=a;
	} else {
		alert('Invalid Input');
	}
}

function computeForm3() {
	if(validateForm()) {
		var n = document.calculator.years.value*12;
		var r = document.calculator.rate.value/(12*100);
		var P = document.calculator.financed.value;
		var temp=1;
		for(var i=0; i<n; i++) {
			temp=temp*(1+r);
		}
		if (temp!=1) {
			var a = round((P*temp*r)/(temp-1),2);
		} else {
			var a = 0;
		}
		var b =  round(r*P,2);
		var c = round(a-b,2);
		getObj('payment').innerHTML=b;
		getObj('payment2').innerHTML=a;
		getObj('payment3').innerHTML=c;
	} else {
		alert('Invalid Input');
	}
}

function validateForm() {
	var reg;
	reg = /^[\d\.]+$/; 
	if(!reg.test(document.calculator.rate.value)) {
		return false;
	}
	reg = /^[\d\.]+$/; 
	if(!reg.test(document.calculator.financed.value)) {
		return false;
	}
	return true;
}

function reset_it() {
	document.calculator.years.value=30;
	document.calculator.rate.value=0;
	document.calculator.financed.value=0;
	document.calculator.payment.value=0;
	computeForm();
}

function reset_it2() {
	document.calculator.years.value=30;
	document.calculator.rate.value=0;
	document.calculator.financed.value=0;
	getObj('payment').innerHTML=0;
	computeForm2();
}

function reset_it3() {
	document.calculator.years.value=30;
	document.calculator.rate.value=0;
	document.calculator.financed.value=0;
	getObj('payment').innerHTML=0;
	getObj('payment2').innerHTML=0;
	getObj('payment3').innerHTML=0;
	computeForm2();
}