function isblank(s)
{
	for(var i = 0; i < s.length; i++)
	{
		var c = s.charAt(i);
		if((c != ' ') && (c != '\n') && (c != '\t'))
			return false;
	}
	//window.alert("true");
	return true;
}

function validate_email(email){
if ((email.indexOf("@")==-1) || (email.indexOf(".")==-1) || (email.indexOf(" ")!=-1) || (email.length<6)) 
	return false;
else
	return true;
}


function validateForm(form)
{

var firstName = form.first_name;
	var lastName = form.last_name;
	var country = form.country;
	var usrChoice = country.selectedIndex;
	var email = form.email;

	
	if(isblank(firstName.value) || (firstName.value == null))
	{
		window.alert("Please enter valid first name.");
		form.first_name.focus();
		return false;
	}
	
	if(isblank(lastName.value) || (lastName.value == null))
	{
		window.alert("Please enter valid last name.");
		form.last_name.focus();
		return false;
	}
	
	if((country.options[usrChoice].value == "0") ||(country.options[usrChoice].value == "1" ))
	{
		window.alert("Please select a country.");
		country.focus();
		return false;
	}
	
	
	if(isblank(email.value) || !(validate_email(email.value)))
	{
		window.alert("Please enter valid email address.");
		email.focus();
		return false;
	}
	
	var product_name = form.product;
	var userChoice_product = product_name.selectedIndex;
	var product_ver = form.version;
	var serial = form.ser_num;
	var purchased_from = form.purchased_from
	var userChoice_purchased = purchased_from.selectedIndex;
	var serial1 = form.ser_num1;
	var serial2=form.ser_num2;
	
	if((product_name.options[userChoice_product].value == "0") ||(product_name.options[userChoice_product].value == "1" ))
	{
		window.alert("Please select a product name.");
		product_name.focus();
		return false;
	}
	
	if(isblank(product_ver.value) || (product_ver.value == null))
	{
		window.alert("Please enter a valid version.");
		product_ver.focus();
		return false;
	}
	
	
	
	if((purchased_from.options[userChoice_purchased].value == "0") ||(purchased_from.options[userChoice_purchased].value == "1" ))
	{
		window.alert("Please select where you purchased the product.");
		purchased_from.focus();
		return false;
	}

	if(isblank(serial.value) || (serial.value == null))
	{
		window.alert("Please enter a first serial number.");
		serial.focus();
		return false;
	}

	if(isblank(serial1.value) || (serial1.value == null))
	{
		window.alert("Please enter second serial number.");
		serial1.focus();
		return false;
	}

	if(isblank(serial2.value) || (serial2.value == null))
	{
		window.alert("Please enter third serial number.");
		serial2.focus();
		return false;
	}

return true;

}