var layerArray = ["calorie_result","sponsor_logo","calorie_input_info","errorMessageDistance","errorMessageWeight"];
function calCalories(){
hideAllLayer();
var distance = document.calories.distance.value;
var weight = document.calories.weight.value;
var milesOrKm = document.calories.distanceType.selectedIndex;
var poundOrKilos = document.calories.weightType.selectedIndex;
// check for invalid values 
if (poundOrKilos == 0)
{
//convert to kilos
weight = weight / 2.2;
}
if (poundOrKilos == 2)
{
//convert stones to kilos
weight = (weight * 14) / 2.2;
}

if (milesOrKm == 0)
{
//convert to kilometers
distance = distance * 1.609;
}

if (isNaN(distance)||(distance <= 0) || (distance > 161)){
showLayer("sponsor_logo");
showLayer("calorie_input_info");
showLayer("errorMessageDistance");
showLayer("calorie_input_info_text");
showLayer("inputBot");
} else if (isNaN(weight)||(weight < 30) || (weight > 363.65)){
showLayer("sponsor_logo");
showLayer("calorie_input_info");
showLayer("errorMessageWeight");
showLayer("calorie_input_info_text");
showLayer("inputBot");
}else{
// compute calories
var calories = weight * distance * 1.036;
// display results
document.getElementById('caloriesNum').innerHTML = " "+Math.round(calories).toString()+" calories";
showLayer("calorie_result");
showLayer("calorie_input_info");
showLayer("feedback");
showLayer("toolLegal");
showLayer("calorie_input_info_text");
showLayer("resultBot");
}
}



function showLayer(layerId){
document.getElementById(layerId).style.display= "";
}
	
function hideLayer(layerId){
	document.getElementById(layerId).style.display= "none";
}

function hideAllLayer(){
	for (i=0;i<layerArray.length;i++){
		hideLayer(layerArray[i]);
	}
}

function isAlphabet(inputVal) {
	inputStr = "" + inputVal;
	for (var i = 0; i < inputStr.length; i ++) {
		var oneChar = inputStr.charAt(i);
		if ((!isNaN(parseInt(oneChar)))){
		return false;
		}
		
	}
	return true;
}

function isNumber(inputVal) {
	inputStr = "" + inputVal;
	for (var i = 0; i < inputStr.length; i ++) {
		var oneChar = inputStr.charAt(i);
		if ((isNaN(parseInt(oneChar)))){
		return false;
		}
	}
	return true;
}