How to add html form user input into a file with JavaScript?

Question

I was wondering how do I put HTML form user input into a file using JavaScript ONLY. I have struggled to find an answer to such a simple question.

Answer 1

Writing data to files on a local filesystem is only supported in modern browsers with a set of limitations, you can google for HTML FileSystem API.

As for writing to a file, this is a basic example:

function onInitFs(fs) {

  fs.root.getFile('log.txt', {create: true}, function(fileEntry) {

    // Create a FileWriter object for our FileEntry (log.txt).
    fileEntry.createWriter(function(fileWriter) {

      fileWriter.onwriteend = function(e) {
        console.log('Write completed.');
      };

      fileWriter.onerror = function(e) {
        console.log('Write failed: ' + e.toString());
      };

      // Create a new Blob and write it to log.txt.
      var blob = new Blob(['Lorem Ipsum'], {type: 'text/plain'});

      fileWriter.write(blob);

    }, errorHandler);

  }, errorHandler);

}

window.requestFileSystem(window.TEMPORARY, 1024*1024, onInitFs, errorHandler);