function formcheck() {
resCheck = 0;
var inputName = document.getElementById('dav_name');
var inputMail = document.getElementById('dav_mail');
var inputComment = document.getElementById('dav_nachricht');
var sendbutton = document.getElementById('dav_senden');
if(inputName.value!="") {
resCheck++;
} else {
if(resCheck >= 1){resCheck--;}
}

if(inputMail.value!="") {
	mailat=inputMail.value.indexOf("@"); 
	maildot=inputMail.value.indexOf("."); 
	if((mailat==-1)||(maildot==-1)) {
		if(resCheck >= 1){resCheck--;}
		}else {
		resCheck++;
		}
} else {
if(resCheck >= 1){resCheck--;}
}
if(inputComment.value!="") {
resCheck++;
} else {
if(resCheck >= 1){resCheck--;}
}

if(resCheck == 3) {
sendbutton.onclick = function(){formsend();};
sendbutton.disabled = false;
} else {
sendbutton.onclick = "";
sendbutton.disabled = true;
}

}
function formsend() {
var mailform = document.getElementById('mailform');
mailform.submit();
}