// JavaScript Document

var KG = 0;
var Meters = 0;
var BMI = 0;

var con = new Array(0.07143, 0.1575, 2.205, 0.4536, 0.002205, 0.0625, 28.35);

var from = new Array(con.length);

function conv(i, Stone) {
	
  var fi = "f"+i;

  var ti = "t"+i;

  from[i] = Stone*1;

  if (isNaN(from[i])) from[i] = 0;

  return Math.round(from[i]*con[i]*10)/10;

}


function conv2meters(feet,inches) {			

	var cm;

	var meters;

	if(isNaN(feet)||isNaN(inches)){

		alert("Please enter numbers only");

		return false;

	}

	cm = ((feet * 30.48) + (inches * .0254) * 100);

	meters = (cm)/100;

	if(meters==0){

		alert("Please enter valid values into the boxes");
		return false;
	}

	return meters;

	

}

function CalculateBMI(){

// Calculate Weight
if(document.getElementById('Kg').value!='Kg'){ KG = document.getElementById('Kg').value; } else 
if((document.getElementById('Stone').value!='Stones')&&(document.getElementById('Pound').value!='Pounds')) {
	var KG = conv(3, ((parseFloat(document.getElementById('Stone').value)*14) + (parseFloat(document.getElementById('Pound').value))));
} 

if(isNaN(KG)){alert('Weight is enter incorrectly');}

// Calculate Height

if(document.getElementById('Meters').value!='Meters'){ Meters = document.getElementById('Meters').value; } else 
if((document.getElementById('Feet').value!='Feet')&&(document.getElementById('Inches').value!='Inches')) {
	var Meters = conv2meters(document.getElementById('Feet').value, document.getElementById('Inches').value);
} 

if(isNaN(Meters)){alert('Height is enter incorrectly');}

	BMI = (KG / (Meters*Meters));
	
	if(!isNaN(BMI)){
	document.getElementById('BMIArea').innerHTML = '<h2>Your Body Mass Index (BMI) is: '+(Math.round(BMI*100)/100)+'</h2>';
	}

}


function ValueSetter(itemField, TheValue){
	
	if(itemField.value == TheValue){itemField.value ='';}
	else if(itemField.value == '') {itemField.value = TheValue;}

}