function CheckZahl(Eingabe){
  var nur_das ="0123456789";
  for (var i = 0; i < Eingabe.length; i++)
   if (nur_das.indexOf(Eingabe.charAt(i))<0 ) return false;
  return true;
 }

 function pruef_ms(ms){
   if(ms<0)
     ms=0;
   if(!CheckZahl(ms))
     ms=0;

   return ms;
 }

 function pruef_kmh(kmh){
   if(kmh<0)
     kmh=0;
   if(!CheckZahl(kmh))
     kmh=0;

   return kmh;
 }

 function pruef_mph(mph){
   if(mph<0)
     mph=0;
   if(!CheckZahl(mph))
     mph=0;

   return mph;
 }


 function pruef_knoten(knoten){
   if(knoten<0)
     knoten=0;
   if(!CheckZahl(knoten))
     knoten=0;

   return knoten;
 }

 function pruef_beaufort(beaufort){
   if(beaufort<0)
     beaufort=0;
   if(beaufort>12)
     beaufort=0;

   if(!CheckZahl(beaufort))
     beaufort=0;

   return beaufort;
 }

 function kmh2ms(kmh){
   ms=0;
   ms=kmh/3.6;

   //return Math.round(ms);
   return ms;
 }

 function kmh2mph(kmh){
   mph=0;
   mph=0.6215*kmh;

   //return Math.round(mph);
   return mph;
 }

 function ms2knoten(ms){
   var knoten=0;
   knoten=1.9438*ms;
   //return Math.round(knoten);
   return knoten;
 }

 function kmh2knoten(kmh){
   knoten=0;
   ms=0;
   ms=kmh2ms(kmh);
   knoten=ms2knoten(ms);

   return knoten;
 }


 function knoten2beaufort(knoten){
 
   if (knoten==0)
    return 0;
   if (knoten<=3)
    return 1;
   if (knoten<=6)
    return 2;
   if (knoten<=10)
    return 3;
   if (knoten<=15)
    return 4;
   if (knoten<=21)
    return 5;
   if (knoten<=27)
    return 6;
   if (knoten<=33)
    return 7;
   if (knoten<=40)
    return 8;
   if (knoten<=47)
    return 9;
   if (knoten<=55)
    return 10;
   if (knoten<=63)
    return 11;
   else
    return 12;   
 }


 function ms2kmh(ms){
   var kmh=0;
   kmh=ms*3.6;
   //return Math.round(kmh);
   return kmh;
 }

 function ms2mph(ms){
   var mph=0;
   var kmh=0;
   kmh=ms2kmh(ms);
   mph=kmh2mph(kmh);
   
   //return Math.round(mph); 
   return mph;
 }

 function mph2kmh(mph){
   var kmh=0;
   kmh=1.609*mph;

   //return Math.round(kmh);
   return kmh;
 }

 function mph2ms(mph){
   var ms=0;
   var kmh=0;

   kmh=mph2kmh(mph);
   ms=kmh2ms(kmh);

   //return Math.round(ms);
   return ms;
 }

 function mph2knoten(mph){
  var knoten=0;
  var ms=0;

  ms=mph2ms(mph);
  knoten=ms2knoten(ms);

  //return Math.round(knoten);
  return knoten;

 }

 function mph2beaufort(mph){
   var beaufort=0;
   var knoten=0;

   knoten=mph2knoten(mph);
   beaufort=knoten2beaufort(knoten);

   return beaufort;

 }



 function ms2beaufort(ms){
   var knoten=0;
   var beaufort=0;
   knoten=ms2knoten(ms);
   beaufort=knoten2beaufort(knoten);

   return beaufort;   
 }

 function kmh2beaufort(kmh){
   beaufort=0;
   ms=0;
   ms=kmh2ms(kmh);
   beaufort=ms2beaufort(ms);

   return beaufort;
 }

 function knoten2ms(knoten){
   var ms=0;
   ms = 0.51444*knoten
   //return Math.round(ms);
   return ms;
 }

 function knoten2mph(knoten){
   var mph=0;
   ms=0;
   ms=knoten2ms(knoten);
   mph=ms2mph(ms);

   return mph;
 }

 function knoten2kmh(knoten){
   var ms=0;
   var kmh=0;
   ms=knoten2ms(knoten);
   kmh=ms2kmh(ms);

   return kmh;
 }


 function beaufort2knoten(beaufort){
   var knoten="0";


   if(beaufort==1)
     knoten="1 tot 3"
   if(beaufort==2)
     knoten="4 tot 6"
   if(beaufort==3)
     knoten="7 tot 10"
   if(beaufort==4)
     knoten="11 tot 15"
   if(beaufort==5)
     knoten="16 tot 21"
   if(beaufort==6)
     knoten="22 tot 27"
   if(beaufort==7)
     knoten="28 tot 33"
   if(beaufort==8)
     knoten="34 tot 40"
   if(beaufort==9)
     knoten="41 tot 47"
   if(beaufort==10)
     knoten="48 tot 55"
   if(beaufort==11)
     knoten="56 tot 63"
   if(beaufort==12)
     knoten=">64"
   
   return knoten;   
 }

 function beaufort2ms(beaufort){
    var ms=0;

   if(beaufort==1)
     ms="0.3 tot 1.5"
   if(beaufort==2)
     ms="1.6 tot 3.3"
   if(beaufort==3)
     ms="3.4 tot 5.4"
   if(beaufort==4)
     ms="5.5 tot 7.9"
   if(beaufort==5)
     ms="8.0 tot 10.7"
   if(beaufort==6)
     ms="10.8 tot 13.8"
   if(beaufort==7)
     ms="13.9 tot 17.1"
   if(beaufort==8)
     ms="17.2 tot 20.7"
   if(beaufort==9)
     ms="20.8 tot 24.4"
   if(beaufort==10)
     ms="24.5 tot 28.4"
   if(beaufort==11)
     ms="28.5 tot 32.6"
   if(beaufort==12)
     ms=">32.6"

    return ms;
 }


 function beaufort2kmh(beaufort){
   var kmh=0;

   if(beaufort==1)
     kmh="1.1 tot 5.4"
   if(beaufort==2)
     kmh="5.5 tot 11.9"
   if(beaufort==3)
     kmh="12.0 tot 19.4"
   if(beaufort==4)
     kmh="19.5 tot 28.4"
   if(beaufort==5)
     kmh="28.5 tot 38.5"
   if(beaufort==6)
     kmh="38.6 tot 49.7"
   if(beaufort==7)
     kmh="49.8 tot 61.5"
   if(beaufort==8)
     kmh="61.6 tot 74.5"
   if(beaufort==9)
     kmh="74.6 tot 87.8"
   if(beaufort==10)
     kmh="87.9 tot 102.2"
   if(beaufort==11)
     kmh="102.3 tot 117.3"
   if(beaufort==12)
     kmh=">117.4"

   return kmh;

 }

 function beaufort2mph(beaufort){
   var mph=0;

   if(beaufort==1)
     mph="0.7 tot 3.5"
   if(beaufort==2)
     mph="3.6 tot 7.5"
   if(beaufort==3)
     mph="7.6 tot 12.2"
   if(beaufort==4)
     mph="12.3 tot 17.8"
   if(beaufort==5)
     mph="17.9 tot 24.0"
   if(beaufort==6)
     mph="24.1 tot 31.0"
   if(beaufort==7)
     mph="31.1 tot 38.3"
   if(beaufort==8)
     mph="38.4 tot 46.4"
   if(beaufort==9)
     mph="46.5 tot 54.7"
   if(beaufort==10)
     mph="54.8 tot 63.6"
   if(beaufort==11)
     mph="63.7 tot 73.0"
   if(beaufort==12)
     mph=">73"


   return mph;
 }



 function WBerechnen(){
   var ms=document.wind.ms.value;
   var knoten=document.wind.knoten.value;
   var beaufort=document.wind.beaufort.value;
   var kmh=document.wind.kmh.value;
   var mph=document.wind.mph.value;
   if (document.wind.ms.value != ""){
     ms=pruef_ms(ms);
     knoten=ms2knoten(ms);
     beaufort=ms2beaufort(ms);
     kmh=ms2kmh(ms);
     mph=ms2mph(ms);
     document.wind.knoten.value=Math.round(knoten);
     document.wind.beaufort.value=Math.round(beaufort);     
     document.wind.ms.value=Math.round(ms);
     document.wind.kmh.value=Math.round(kmh);
     document.wind.mph.value=Math.round(mph);
     return;
   }
   if (document.wind.knoten.value != ""){
     knoten=pruef_knoten(knoten);
     ms=knoten2ms(knoten);
     beaufort=knoten2beaufort(knoten);
     kmh=knoten2kmh(knoten);
     mph=knoten2mph(knoten);
     document.wind.ms.value=Math.round(ms);
     document.wind.beaufort.value=Math.round(beaufort);     
     document.wind.knoten.value=Math.round(knoten);
     document.wind.kmh.value=Math.round(kmh);
     document.wind.mph.value=Math.round(mph);
     return;
   }
   if (document.wind.beaufort.value != ""){
     beaufort=pruef_beaufort(beaufort);
     ms=beaufort2ms(beaufort);
     knoten=beaufort2knoten(beaufort);
     kmh=beaufort2kmh(beaufort);
     mph=beaufort2mph(beaufort);
     document.wind.ms.value=ms;
     document.wind.knoten.value=knoten;     
     document.wind.beaufort.value=beaufort;
     document.wind.kmh.value=kmh;
     document.wind.mph.value=mph;
     return;
   }
   if (document.wind.kmh.value != ""){
     kmh=pruef_kmh(kmh);
     ms=kmh2ms(kmh);
     knoten=kmh2knoten(kmh);
     beaufort=kmh2beaufort(kmh);
     mph=kmh2mph(kmh);
     document.wind.ms.value=Math.round(ms);
     document.wind.knoten.value=Math.round(knoten);     
     document.wind.beaufort.value=Math.round(beaufort);
     document.wind.kmh.value=Math.round(kmh);
     document.wind.mph.value=Math.round(mph);
     return;
   }
   if (document.wind.mph.value != ""){
     mph=pruef_mph(mph);
     ms=mph2ms(mph);
     knoten=mph2knoten(mph);
     beaufort=mph2beaufort(mph);
     kmh=mph2kmh(mph);
     document.wind.ms.value=Math.round(ms);
     document.wind.knoten.value=Math.round(knoten);     
     document.wind.beaufort.value=Math.round(beaufort);
     document.wind.kmh.value=Math.round(kmh);
     document.wind.mph.value=Math.round(mph);
     return;
   }


 }


 function WLoeschen(){
   with(document.wind){
     ms.value="";
     knoten.value="";
     beaufort.value="";
     kmh.value="";
     mph.value="";
   }
 }

 function neu_knoten(){
   with(document.wind){
     knoten.value=Math.round(knoten.value);
     ms.value="";
     beaufort.value="";
     kmh.value="";
     mph.value="";
   }
 }