function validate_required(field,alerttxt)
{
with (field)
{
if (value==null||value=="")
  {alert(alerttxt);return false;}
else {return true}
}
}function validate_form(thisform)
{
with (thisform)
{
if (validate_required(realname,"Please enter your name")==false)
  {realname.focus();return false;}
if (validate_required(phone,"Please enter your phone number")==false)
  {phone.focus();return false;}  
if (validate_required(email,"Please enter your email address")==false)
  {email.focus();return false;} 
if (validate_required(interestedIn,"Please select the product you are interest in")==false)
  {interestedIn.focus();return false;}
if (validate_required(referredBy,"Please let us know how you heard of this offer")==false)
  {referredBy.focus();return false;} 
}
}