function validateFormulier(formulier) {
	check = true;
	for (i=0;i<formulier.length;i++){
		var veld = formulier.elements[i];
		
		if(veld.name == 'naam'){
			if(!validateEmpty(veld)){
				check = printError("Geen naam ingevuld");
				return false;
			}
		}
		if(veld.name == 'telefoon'){
			if(!validateEmpty(veld)){
				check = printError("Geen telefoonnummer ingevuld");
				return false;
			}
		}
		if(veld.name == 'email'){
			if(!validateEmpty(veld)){
				check = printError("Geen emailadres ingevuld");
				return false;
			}
		}
		if(veld.name == 'email'){
			if(!validateEmail(veld)){
				check = printError("Het ingevoerde emailadres is niet geldig");
				return false;
			}
		}
	}
	
	return check
}

function printError(s)
{
	alert("Fout: "+s);
	return false;
}

function trim(s)
{
  return s.replace(/^\s+|\s+$/, '');
}

function validateEmail(fld) {
    var error="";
    var tfld = trim(fld.value);                        // value of field with whitespace trimmed off
    var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
    var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;
   
    if (fld.value == "") {
        fld.style.background = '#F4DFEF';
        error = "You didn't enter an email address.\n";
    } else if (!emailFilter.test(tfld)) {              //test email for illegal characters
        fld.style.background = '#F4DFEF';
        error = "Please enter a valid email address.\n";
    } else if (fld.value.match(illegalChars)) {
        fld.style.background = '#F4DFEF';
        error = "The email address contains illegal characters.\n";
    } else {
        fld.style.background = 'White';
    }
	if(error != ""){
	 	return false;	
	}else{
		return true;	
	}
}

function validatePhone(fld) {
    var error = "";
    var stripped = fld.value.replace(/[\(\)\.\-\ ]/g, '');    

   if (fld.value == "") {
        error = "You didn't enter a phone number.\n";
        fld.style.background = '#F4DFEF';
    } else if (isNaN(parseInt(stripped))) {
        error = "The phone number contains illegal characters.\n";
        fld.style.background = '#F4DFEF';
    } else if (!(stripped.length == 10)) {
        error = "The phone number is the wrong length. Make sure you included an area code.\n";
        fld.style.background = '#F4DFEF';
    }
    if(error != ""){
	 	return false;	
	}else{
		return true;	
	}
}

function validateEmpty(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#F4DFEF'; 
        error = "Niet alle verplichte velden zijn ingevuld.\n"
    } else {
        fld.style.background = 'White';
    }
    if(error != ""){
	 	return false;	
	}else{
		return true;	
	}  
}