function check(offerte)
{
	var error = false;
	if (offerte.merk.value == "") { alert("Please fill in a brand."); offerte.merk.focus(); error = true; return false; }
	if (offerte.type.value == "") { alert("Please fill in a type"); offerte.type.focus(); error = true; return false; }
	if (offerte.wielbasis.value == "") { alert("Please in a wheelbase"); offerte.wielbasis.focus(); error = true; return false; }
	if (offerte.bouwjaar.value == "") { alert("Please fill in a construction date"); offerte.bouwjaar.focus(); error = true; return false; }
	
	if (offerte.voorletters.value=="") { alert("Please fill in your first name"); offerte.voorletters.focus(); error = true; return false; }
	if (offerte.naam.value=="") { alert("Please fill in your familyname"); offerte.naam.focus(); error = true; return false; }
	if (offerte.email_from.value == "" || offerte.email_from.value.indexOf('@',0) == -1 || offerte.email_from.value.indexOf ('.',0) == -1) { alert("Please fill in your email address"); offerte.email_from.focus(); error = true; return false;}
	if (offerte.telefoon.value=="") { alert("Please fill in your telephone number"); offerte.telefoon.focus(); error = true; return false; }
	if (offerte.reactie.value=="") { alert("Please fill in a reaction"); offerte.reactie.focus(); error = true; return false; }
		
	if(!error)
		offerte.submit();

}