function decode_utf8(utftext) {
         var plaintext = ""; var i=0; var c=c1=c2=0;
         // while-Schleife, weil einige Zeichen uebersprungen werden
         while(i<utftext.length)
             {
             c = utftext.charCodeAt(i);
             if (c<128) {
                 plaintext += String.fromCharCode(c);
                 i++;}
             else if((c>191) && (c<224)) {
                 c2 = utftext.charCodeAt(i+1);
                 plaintext += String.fromCharCode(((c&31)<<6) | (c2&63));
                 i+=2;}
             else {
                 c2 = utftext.charCodeAt(i+1); c3 = utftext.charCodeAt(i+2);
                 plaintext += String.fromCharCode(((c&15)<<12) | ((c2&63)<<6) | (c3&63));
                 i+=3;}
             }
         return plaintext;
     }
     
     function send_mail() {
     	var vorname   = document.getElementById('vorname').value;
     	var zuname    = document.getElementById('name').value;
     	var email     = document.getElementById('email').value;
     	var uhrzeit   = document.getElementById('uhrzeit').value;
     	var telefon   = document.getElementById('telefon').value;
     	var kommentar = document.getElementById('kommentar').value;
     	
     	
     	var test = 0;
     	var errortext = 'Bitte füllen Sie noch die Angaben in den folgenden Feldern aus:';
     	if (vorname.length == 0)  { test = 1; errortext += '\n- Vorname'; }
     	if (zuname.length == 0)   { test = 1; errortext += '\n- Name'; }
     	if (email.length == 0)    { test = 1; errortext += '\n- E-Mail-Adresse'; }
     	if (uhrzeit == "")        { test = 1; errortext += '\n- Tag/Uhrzeit'; }
     	if (telefon.length == 0)  { test = 1; errortext += '\n- Telefonnummer'; }
     	    	
    	if (test == 0) {
				return true;
     	} else {
     		alert(errortext);
     		return false;
     	}
     }