function checkForm(tf)
{
	if(tf.first_name.value == "")
	{
		alert("Please enter your first name");
		tf.first_name.focus();
		return false;	
	}
	
	if(tf.email.value == "")
	{
		alert("Please enter your email address");
		tf.email.focus();
		return false;	
	}
	
	if(tf.phone.value.length < 8)
	{
		alert("Please enter your phone number");
		tf.phone.focus();
		return false;	
	}
	
	if(tf.postcode.value.length != 4)
	{
		alert("Please enter your postcode");
		tf.postcode.focus();
		return false;	
	}
	
	if(tf.captcha_code.value.length != 4)
	{
		alert("Please enter the security code");
		tf.captcha_code.focus();
		return false;	
	}	
	
	return true;				
}