function isReferenceValid(ref) {
	var patt = /^[A-z0-9]{2,3}\d{7}$/;
	if (patt.test(ref)) {
		return true;
	}
}

function isPostcodeValid(post) {
	var patt = /^[A-z]{1,2}\d[A-z0-9]? \d[A-z]{2}$/;
	if (patt.test(post)) {
		return true;
	}
}

function checkRefAndPost(form, refErrId, refErrMsg, postErrId, postErrMsg) {
	var refErr = document.getElementById(refErrId);
	var postErr = document.getElementById(postErrId);
	
	if (!isReferenceValid(form.Ref.value)) {
		refErr.innerHTML = refErrMsg;
	} else if (refErr.innerHTML != '') {
		refErr.innerHTML = '';
	}
	if (!isPostcodeValid(form.Post.value)) {
		postErr.innerHTML = postErrMsg;
	} else if (postErr.innerHTML != '') {
		postErr.innerHTML = '';
	}
	
	if (refErr.innerHTML != '' || postErr.innerHTML != '') {
		return false;
	}
}

function stripSpaces(field) {
	field.value = field.value.replace(/\s/, '');
}

function addPostcodeSpace(field) {
	var patt = /\s/;
	if (!patt.test(field.value)) {
		field.value = field.value.replace(/^(.{2,4})(.{3})$/,"$1 $2");
	}
}

function removeDefaultValue(field, defaultValue) {
	if (field.value == defaultValue) {
		field.value = '';
	}
}

function addDefaultValue(field, defaultValue) {
	if (field.value == '') {
		field.value = defaultValue;
	}
}