text: Q:
  
  Saving the result of a function with for-loop as csv file in JavaScript
  
  I searched a lot here in Stack Overflow and in Google but unfortunately no answer.
  I wrote a code in JS, it give me such a "expectable and correct" result:
  W,52.xxxxx,10.1
  W,52.xxxxx,10.2
  W,52.xxxxx,10.3
  W,52.yyyyy,10.1
  W,52.yyyyy,10.2
  W,52.yyyyy,10.3
  
  The problem is that there is a too large list of such rows, I can't copy it fully in Android, so I would to save this list as csv file instead to display it on the webpage via the command 
  "document.write"
  
  I modified my code with the help of other peoples' codes but it doesnt work.
  I become the word "undefined" instead of the list of data that would be inside the csv file :(
  Code is here:
  <!DOCTYPE html>
  <html>
      <head>
          <title>Page Title</title>
      </head>
      <body>
  
      </body>
      <script>
          function convertTo()
  {
  
      var lon,lat;
  
      for(lat = 52 + (1/3600) ; lat <= 52 + (3/3600) ; lat=lat+(1/3600))
  
      {
  
         for(lon = 9 + (1/3600) ; lon<= 9 + (4/3600) ; lon=lon+(1/3600))
             {
  
        document.write("W,"+lat+","+lon+"<br>")
  
             }
      }
  
  };
  
  var CSV = convertTo();
  
  window.URL = window.webkitURL || window.URL;
  
  var contentType = 'text/csv';
  
  var csvFile = new Blob([CSV], {type: contentType});
  
  var a = document.createElement('a');
  
  a.download = 'my.csv';
  
  a.href = window.URL.createObjectURL(csvFile);
  
  a.textContent = 'Download as CSV';
  
  a.dataset.downloadurl = [contentType,
  
  a.download, a.href].join(':');
  
  document.body.appendChild(a);
  
      </script>
  </html>
  
  Any help please!
  Hint: I am beginner with JS
  Edit:
  Here I got the code the export into csv file the I added and modified with my code:
  Lee Kowalkowski's answer
  
  A:
  
  Hi Sorry you can use below code also working code in jsfiddle
  Script
  function convertTo()
  {
  var lon,lat;
  var str ='';
  for(lat = 52 + (1/3600) ; lat <= 52 + (3/3600) ; lat=lat+(1/3600))
  {
     for(lon = 9 + (1/3600) ; lon<= 9 + (4/3600) ; lon=lon+(1/3600))
         {
    str+="W;"+lat+";"+lon+"\n";
         }
  }
  return str;
  };
  var CSV = convertTo();
  window.URL = window.webkitURL || window.URL;
  var contentType = 'text/csv';
  var csvFile = new Blob([CSV], {type: contentType});
  var a = document.createElement('a');
  a.download = 'my.csv';
  a.href = window.URL.createObjectURL(csvFile);
  a.textContent = 'Download as CSV';
  a.dataset.downloadurl = [contentType,
  a.download, a.href].join(':');
  document.body.appendChild(a);
  
  