function isValidContactForm()
{
	strAlertIntroText = "De volgende velden zijn niet (goed) ingevuld"
	focusField        = "";
	strAlertMsg       = "";
	var strBadFields  = "";
	objForm           = document.contactformulier;
	
	if (isNotEmpty(objForm, "strFullName", "lblFullName", "")==false) { strBadFields += "> Uw naam \n"; }
	if (isNotEmpty(objForm, "strPhone", "lblPhone", "")==false) { strBadFields += "> Uw telefoonnummer \n"; }
	if (isEmail(objForm, "strEmailAddress", "lblEmailAddress", "")==false) { strBadFields += "> Uw emailadres \n"; }
	if (isNotEmpty(objForm, "strMessage", "lblMessage", "")==false) { strBadFields += "> Uw bericht \n"; }
	
	if (strBadFields != "")  {
		alert(strAlertIntroText+ ":\n"+ strBadFields);			
		return false;
	} else  {
		return true;
	}
}