function isNumeric(text, validChars) {
	var isNumber=true;
	var char;
	for (i = 0; i < text.length && isNumber == true; i++) {
		char = text.charAt(i); 
		if ((validChars.indexOf(char) == -1)||(text==null)||(text=='')) {
			isNumber = false;
		}
	}
	return isNumber;
}

function getInt(val) {
	if (val.length == 0) { return 0; }
	if (isNumeric(val, "0123456789")) { return parseInt(val); } else { return 0; }
}

function validateForm(form) {
	var result = true;
	var numberOfFittings = document.getElementById("numberOfFittings").value;
	if (!isNumeric(numberOfFittings, "0123456789")) {
		document.getElementById("e_numberOfFittings").style.visibility = "visible";
		result = false;
	} else {
		document.getElementById("e_numberOfFittings").style.visibility = "hidden";		
	}
	var daysPerWeek = getInt(document.getElementById("daysPerWeek").value);
	if (daysPerWeek < 1 || daysPerWeek > 7) {
		document.getElementById("e_daysPerWeek").style.visibility = "visible";
		result = false;
	} else {
		document.getElementById("e_daysPerWeek").style.visibility = "hidden";
	}
	var hoursPerDay = getInt(document.getElementById("hoursPerDay").value);
	if (hoursPerDay < 1 || hoursPerDay > 24) {
		document.getElementById("e_hoursPerDay").style.visibility = "visible";
		result = false;
	} else {
		document.getElementById("e_hoursPerDay").style.visibility = "hidden";
	}
	var centPerKwh = document.getElementById("centPerKwh").value;
	if (!isNumeric(centPerKwh, "0123456789.")) {
		document.getElementById("e_centPerKwh").style.visibility = "visible";
		result = false;
	} else {
		document.getElementById("e_centPerKwh").style.visibility = "hidden";
	}
	return result;
}