function bookThis(args) {
	myWidth=400;
	myHeight=400;
	var myLeft = (screen.width-myWidth-400)/2;
	var myTop = (screen.height-myHeight)/2;
	window.open(args,"bookPopUp","width="+myWidth+",height="+myHeight+",left="+myLeft+",top="+myTop);
}

function check_empty(text) {
	return (text.length > 0);
}

function submitForm(args) {
	if (args==1) {
		var fieldsToHave = new Array("name","vorname","telefon","email","strasse","plz","stadt","land");
	} else {
		var fieldsToHave = new Array("name","vorname","telefon","email");
	}
	var errorText="";
	for (var i=0; i<fieldsToHave.length; i++){
		if (!check_empty(document.form[fieldsToHave[i]].value) ){
			errorText+=document.form[fieldsToHave[i]].name+" ";
		}
	}
	
	if (errorText.length>0) {
		alert("Bitte folgende Felder ausfüllen:\n"+errorText);
	} else {
		document.form.submit();
	}
}