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

function validate_form(thisform)
{
	with (thisform)
	{
		if (validate_required(first_name,"Please enter your name")==false)
		  {first_name.focus();return false}
	
		if (validate_required(last_name,"Please enter your surname")==false)
		  {last_name.focus();return false}
		  
		if (validate_required(email,"Please enter your email address")==false)
		  {email.focus();return false}
	}
}