function checksubmit(){
	validRegExp = /^[^@]+@[^@]+.[a-z]{2,}$/i;

	var form = document.contact_form;

	if(form.lastname.value=='') return false;
	if(form.firstname.value=='') return false;

	if(form.firma.value=='') return false;
	if(form.address.value=='') return false;
	if(form.kod.value=='') return false;
	if(form.city.value=='') return false;
	if(form.phone.value=='') return false;
	if(form.fax.value=='') return false;
	if(form.mobile.value=='') return false;
	if(form.email.value=='') return false;
	if(form.email.value!=''&&!document.getElementById('email').value.match(validRegExp)) { alert('Bitte teilen Sie uns Ihre aktuelle Emailadresse mit'); return false; }
	if(form.theme.value=='') return false;
	if(form.message.value=='') return false;

	return true;
}