title: Using javascript to save base64 String to excel (.xls) file?
body: <p>I converted a excel file as base64 String as web backend side, and could recover it as excel file as expected with Java code below:
  String destinationPath = "e:\out1.xls";</p>
  
  <pre><code>        //decode Base64 String to excel file
          FileOutputStream fos = new FileOutputStream(destinationPath); 
          bytes = new sun.misc.BASE64Decoder().decodeBuffer(content);
          fos.write(bytes);
          fos.flush();
          fos.close();
  </code></pre>
  
  <p>I can response frontend with base64 string, but I always got messy code when I tried to export it as excel (.xls) file using javascript. Below is the code:
  onClick: function(){</p>
  
  <pre><code>// below is base64 String snippet.
          var base64Str = "0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAOwADAP7/CQAGAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAA\r\nEAAA/v///wAAAAD+////AAAAAAEAAAD/////////////////////////////////////////////\r\n////////////////////////////////////////////////////////////////////////////\r\n////////////////////////////////////////////////////////////////////////////\r\n////////////////////////////////////////////////////////////////////////////\r\n////////////////////////////////////////////////////////////////////////////\r\n////////////////////////////////////////////////////////////////////////////\r\n////////////////////////////////////////////////////////////////////////////\r\n//////////////////////////////////////////////////////////////////////////9S\r\nAG8AbwB0ACAARQBuAHQAcgB5AAAAAAAAAAAAAA .........";
  
          base64Str = base64Str.replace(/\\r\\n/g,"");
  
          var decoder = Ext.util.Base64.decode(fileStr);
          testApp.view.main.FileExport.saveAs(decoder,'SHANGTOUDI_JF_20180320_0800.xls','UTF-8');
      }
  </code></pre>
  
  <p>Need to say, I can use this method to export txt file successfully. Any suggestion are appreciated.</p>