function checkForm(which){
	var empty = false;
	for (i=0;i<which.length;i++){
		var tempobj=which.elements[i];		
		if (in_array(tempobj.name,verplicht)){
			if(tempobj.type=="text"){
				tempobj.style.background="#FFFFFF";
			}
			if((tempobj.type=="text" || tempobj.type=="textarea") && tempobj.value==""){
				tempobj.style.background="#FF818C";
				empty = true;
			}
			if(tempobj.type=="text" && tempobj.value!='' && tempobj.name=='naam'){
				var naam=/^[a-z A-Z\.\-]*$/;
				if(tempobj.value.length < 3){
					document.forms.gegevens.naam.style.background="#FF818C";
					alert("Een moet langer zijn dan 2 karakters.");
					return false;
				}
				if(!(naam.test(tempobj.value))){
					document.forms.gegevens.naam.style.background="#FF818C";
					alert("Een naam mag geen cijfers bevatten.");
					return false;
				}
			}
			if(tempobj.type=="text" && tempobj.value!='' && tempobj.name=='email'){
				var email=/^[_\.0-9a-z-]+\@([0-9a-z][0-9a-z-]*\.)+([a-z]{2,4})+$/i
				if(!(email.test(tempobj.value))){
					tempobj.style.background="#FF818C";
					alert("Het ingevoerde email adres is niet geldig.");
					return false;
				}
			}
		}
	}
	if(empty){
		alert("Niet alle velden zijn ingevuld.");
		return false;
	} else {
		return true;
	}
}
function in_array(the_needle, the_haystack){
	var the_hay = the_haystack.toString();
	if(the_hay == ''){
		return false;
	}
	var the_pattern = new RegExp(the_needle, 'g');
	var matched = the_pattern.test(the_haystack);
	return matched;
}