function validate_required(field,alerttxt)
{
with (field)
{
  if (value==null||value=="")
  {
  alert(alerttxt);return false;
  }
  else
  {
  return true;
  }
}
}

function validate_email(field,alerttxt)
{
with (field)
{
apos=value.indexOf("@");
dotpos=value.lastIndexOf(".");
if (apos<1||dotpos-apos<2) 
  {alert(alerttxt);return false;}
else {return true;}
}
}

function validate_form(thisform)
{
with (thisform)
{
if (validate_required(first_name,"First name must be filled out!")==false)
    {first_name.focus();return false;}
else if(validate_required(last_name,"Last name must be filled out!")==false)
    {last_name.focus();return false;}
else if(validate_required(phone,"Phone must be filled out!")==false)
  {phone.focus();return false;}
else if(validate_email(email,"Not a valid e-mail address!")==false)
  {email.focus();return false;}
}
}