// Script for the BMI calculator

var h_imperial = 1; //flags for input modes
var w_imperial = 1;
var pounds_to_kgs = 2.204623;
var inches_to_meters = 39.4
var h_ft, h_ins, h_m, h_cms;
var w_st, w_pds, w_kgs;
var h,w, w1;
var weight_in_pounds;

function dispnum(x) {
	x = Math.floor(x*10)/10; // rounded off to two decimal places
	return(x);
}

function clearvalues(){ // clears all the contents of the form

	document.data.height_feet.value=''
	document.data.height_inches.value=''
	document.data.height_meters.value=''
	document.data.height_cms.value=''
	document.data.weight_stones.value=''
	document.data.weight_pounds.value=''
	document.data.weight_kgs.value=''
	document.data.bmi.value=''
	document.data.expl.value=''
	document.data.max_stones.value=''
	document.data.max_pounds.value=''
	document.data.max_kgs.value=''
}

function initialise() { // initialise the variables

	if (document.data.height_feet.value == '') {
		document.data.height_feet.value = 0;
	}
	if (document.data.height_inches.value == '') {
		document.data.height_inches.value = 0;
	}
	if (document.data.height_meters.value == '') {
		document.data.height_meters.value = 0;
	}
	if (document.data.height_cms.value == '') {
		document.data.height_cms.value = 0;
	}
	if (document.data.weight_stones.value == '') {
		document.data.weight_stones.value = 0;
	}
	if (document.data.weight_pounds.value == '') {
		document.data.weight_pounds.value = 0;
	}
	if (document.data.weight_kgs.value == '') {
		document.data.weight_kgs.value = 0;
	}
}

function compute() { // the main routine

	initialise();

	h_ft = parseFloat(document.data.height_feet.value);
	h_ins = parseFloat(document.data.height_inches.value);
	h_m = parseFloat(document.data.height_meters.value);
	h_cms = parseFloat(document.data.height_cms.value);

	if (h_imperial) {
		h = ((h_ft*12)+h_ins)
		h /= inches_to_meters; }	// convert inches to metres
	else {
		h = ((h_m*100)+h_cms)/100;
	}

	if (h <= 1.22) {
		alert(dispnum(h)+" Metres seems to be too short\n\nPlease try again.");
	}

	if (h >= 2.13) {
		alert(dispnum(h)+" Metres seems to be too tall\n\nPlease try again.");
	}

	w_st = parseFloat(document.data.weight_stones.value);
	w_pds = parseFloat(document.data.weight_pounds.value);
	w_kgs = parseFloat(document.data.weight_kgs.value);

	if (w_imperial) {
		w = ((w_st*14)+w_pds);
		w1 = w;
		w /= pounds_to_kgs;} // pounds to kgs }
	else {
		w=w_kgs;
	}

	if (w <= 25) {
		alert(dispnum(w)+" Kgs? Thats much too light\n\nPlease try again.");
	}

	if (w >= 227) {
		alert(dispnum(w)+" Kgs? Thats much too heavy\n\nPlease try again.");
	}

	bmi = w / (h*h);

	max_kgs = 25*h*h;
	weight_in_pounds = (max_kgs*2.2);

	document.data.bmi.value = dispnum(bmi);
	if (bmi < 20 )
		document.data.expl.value = "Underweight - you may need to put weight on";
	if (bmi >= 20 && bmi <= 25 )
		document.data.expl.value = "OK - ideal weight range, try to maintain";
	if (bmi > 25 && bmi <= 30 )
		document.data.expl.value = "Overweight - make sure your weight doesn't rise";
	if (bmi > 30 )
		document.data.expl.value = "Obese - important to lose weight";

	max_imperial = (weight_in_pounds/14)*10;
	
	max_imperial = Math.round(max_imperial);
	max_imperial = max_imperial/10;
	
	document.data.max_stones.value = Math.floor(max_imperial);
	
	temp1 = max_imperial - (Math.floor(max_imperial));
	
	temp1 = Math.round(temp1*10);
	document.data.max_pounds.value = Math.round(temp1*1.4);
	
	document.data.max_kgs.value = dispnum(max_kgs);
}

/*millimol converter begins */
function convertLDL(millimolForm) {
	var source = millimolForm.elements["sourceval"].value;
	var cnvtype = millimolForm.elements["lstcnvtype"].selectedIndex;
	var dest;
	if (cnvtype == 0) {
		dest = Math.round(source * 38.7);
	} else {
		dest = source / 38.7;
		dest = Math.round(dest * 10) / 10;
	}
	millimolForm.elements["destval"].value = dest;
 }
 
function convertTG(millimolForm) {
	var source = millimolForm.elements["tgsourceval"].value;
	var cnvtype = millimolForm.elements["tglstcnvtype"].selectedIndex;
	var dest;
	if (cnvtype == 0) {
		dest = Math.round(source * 88.57396);
	} else {
		dest = Math.round(source * 0.01129);
	}
	millimolForm.elements["tgdestval"].value = dest;
}
/*millimol converter ends */