function validateForm() {
	var usageDom = document.getElementById("usageDomestic").checked;
	var usageCom = document.getElementById("usageCommerical").checked;
	var outdoorYes = document.getElementById("outdoorYes").checked;
	var outdoorNo = document.getElementById("outdoorNo").checked;
	var budget = document.getElementById("unitBudget").value;
	var quantity = document.getElementById("unitQuantity").value;
	var areaSize = document.getElementById("areaSize").value;
	var typeGrid = document.getElementById("unitTypeGrid").checked;
	var typeGlue = document.getElementById("unitTypeGlue").checked;
	var mountFree = document.getElementById("chkFreestand").checked;
	var mountWall = document.getElementById("chkWallmount").checked;
	var mountSuspend = document.getElementById("chkSuspend").checked;
	
	if (!is_numeric(budget)) {
		alert("Form input error: budget is not a number (question 3)");
		return false;
	}
	if (quantity != 1 && quantity != 10) {
		alert("Form input error: please select a valid quantity (question 4)");
	}
	if (!is_numeric(areaSize)) {
		alert("Form input error: area size is not a number (question 5)");
		return false;
	}
	if (usageDom != true && usageCom != true) {
		alert("Form input error: please answer question 1");
		return false;
	}	
	if (outdoorYes != true && outdoorNo != true) {
		alert("Form input error: please answer question 2");
		return false;
	}
	if (typeGrid != true && typeGlue != true) {
		alert("Form input error: please answer question 6");
		return false;
	}
	/* if (mountFree != true && mountWall != true && mountSuspend != true) {
		alert("Form input error: please answer question 7");
		return false;
	} */
	return true;
}
function is_numeric(x) {
return (x!=null && !isNaN(x));
}