function Prompt(Ctrl,PromptStr) {
	alert (PromptStr)
	if (mwtForm.hSize.value == ""){
		Ctrl.focus();
	}
	if (mwtForm.wSize.value == ""){
		Ctrl.focus();
	}
	if (mwtForm.bWeight.value == ""){
		Ctrl.focus();
	}
	if (mwtForm.hArea.value == ""){
		Ctrl.focus();
	}
	if (mwtForm.wArea.value == ""){
		Ctrl.focus();
	}
	return;
}

function testBlank(objField,FieldName) {
	var strField = new String(objField.value);

	if (objField.value == "") {
		Prompt (objField, "\""+FieldName+"\" cannot be blank.")
		return (false);
	} else {
		return (true);
	}
}

function testNumber(objField,FieldName) {
	var numField = objField.value;

	if (isNaN(numField)) {
		Prompt (objField, "\""+FieldName+"\" must be a valid number.")
		return (false);
	}

	numField = parseFloat(numField);

	if (numField> 0) {
		return (true);
	} else {
		Prompt (objField, "\""+FieldName+"\" must be a number greater than 0.")
		return (false);
	}
}

function testValue(objField,FieldName) {
	if (!testBlank(objField,FieldName)) return false;
	if (!testNumber(objField,FieldName)) return false;
	return true;
}

function validateForm() {
	var form = document.mwtForm;

	if (!testValue(form.hSize,"Sheet Size (Height)")) return false;
	if (!testValue(form.wSize,"Sheet Size (Width)")) return false;
	if (!testValue(form.bWeight,"Basis Weight")) return false;
	if (!testValue(form.hArea,"Basic Size (Height)")) return false;
	if (!testValue(form.wArea,"Basic Size (Width)")) return false;

	hArea = form.hArea.value;
	wArea = form.wArea.value;

	if (hArea > 0 && wArea > 0) {
		mw = mWeight(form.hSize.value,form.wSize.value,form.bWeight.value,hArea,wArea);
		document.mwtForm.Answer.value = mw;
		return true;
	} else {
		return false;
	}
}


function mWeight(hSize,wSize,bWeight,hArea,wArea) {
	var ream = reamWeight(hSize,wSize,bWeight,hArea,wArea);
	var round = roundingM(ream,hSize,wSize);
	return round;
}

function reamWeight(hSize,wSize,bWeight,hArea,wArea) {
	return ((hSize * wSize) * bWeight) / (hArea * wArea);
}


function roundingM(val,hSize,wSize) {
	var sheet = hSize * wSize;
	if (sheet > 863) {
		rndM = (Math.round (val,0)) * 2;
		return formatnumber (rndM,0);
	} else if (sheet < 864 && sheet > 335) {
		val = val * 2;
		rndM = (Math.round (val,0) / 2) * 2;
		return formatnumber (rndM,0);
	} else {
		val = val * 100;
		rndM = (Math.round (val,2) / 100) * 2;
		return formatnumber (rndM,2);
	}
}


function formatnumber(val,places) {
	var power = 1;
	if (places> 0) { power = Math.pow(10,places); }
	var rnd = (Math.ceil(val * power)/power) + "";
	var pos = rnd.indexOf(".");
	if (pos>= 0) {
		var diff = places-(rnd.length-(pos+1));
	} else {
		var diff = places;
		if (places> 0) { rnd += "."; }
	}
	for (x = 0; x < diff; x++) { rnd += "0"; }
    return rnd;
}

function setValues() {
	var form = document.mwtForm;
	var area = form.Area.value;

	if (area == 0) { form.hArea.value = ""; form.wArea.value = ""; }
	if (area == 1) { form.hArea.value = 17; form.wArea.value = 22; }
	if (area == 2) { form.hArea.value = 25; form.wArea.value = 38; }
	if (area == 3) { form.hArea.value = 24; form.wArea.value = 36; }
	if (area == 4) { form.hArea.value = 25.5; form.wArea.value = 30.5; }
	if (area == 5) { form.hArea.value = 22.5; form.wArea.value = 30.5; }
	if (area == 6) { form.hArea.value = 24; form.wArea.value = 36; }
	if (area == 7) { form.hArea.value = 20; form.wArea.value = 26; }
	if (area == 8) { form.hArea.value = 25; form.wArea.value = 38; }
	if (area == 9) { form.hArea.value = 20; form.wArea.value = 26; }
	if (area == 10) { form.hArea.value = 288; form.wArea.value = 1; }
}