[javascript] get the data of uploaded file in javascript

I want to upload a csv file and process the data inside that file. What is the best method to do so? I prefer not to use php script. I did the following steps. But this method only returns the file name instead of file path.So i didnt get the desired output.

<form id='importPfForm'>
<input type='file' name='datafile' size='20'>
<input type='button' value='IMPORT' onclick='importPortfolioFunction()'/>
</form>

function importPortfolioFunction( arg ) {
    var f = document.getElementById( 'importPfForm' );
    var fileName= f.datafile.value;   
}

So how can i get the data inside that file?

This question is related to javascript html ajax file-upload

The answer is


FileReaderJS can read the files for you. You get the file content inside onLoad(e) event handler as e.target.result.


The example below shows the basic usage of the FileReader to read the contents of an uploaded file. Here is a working Plunker of this example.

<!DOCTYPE html>
<html>
  <head>
    <script src="script.js"></script>
  </head>

  <body onload="init()">
    <input id="fileInput" type="file" name="file" />
    <pre id="fileContent"></pre>
  </body>
</html>

script.js

function init(){
  document.getElementById('fileInput').addEventListener('change', handleFileSelect, false);
}

function handleFileSelect(event){
  const reader = new FileReader()
  reader.onload = handleFileLoad;
  reader.readAsText(event.target.files[0])
}

function handleFileLoad(event){
  console.log(event);
  document.getElementById('fileContent').textContent = event.target.result;
}

The example below is based on the html5rocks solution. It uses the browser's FileReader() function. Newer browsers only.

See http://www.html5rocks.com/en/tutorials/file/dndfiles/#toc-reading-files

In this example, the user selects an HTML file. It uploaded into the <textarea>.

<form enctype="multipart/form-data">
<input id="upload" type=file   accept="text/html" name="files[]" size=30>
</form>

<textarea class="form-control" rows=35 cols=120 id="ms_word_filtered_html"></textarea>

<script>
function handleFileSelect(evt) {
    var files = evt.target.files; // FileList object

    // use the 1st file from the list
    f = files[0];

    var reader = new FileReader();

    // Closure to capture the file information.
    reader.onload = (function(theFile) {
        return function(e) {

          jQuery( '#ms_word_filtered_html' ).val( e.target.result );
        };
      })(f);

      // Read in the image file as a data URL.
      reader.readAsText(f);
  }

  document.getElementById('upload').addEventListener('change', handleFileSelect, false);
</script>

Examples related to javascript

need to add a class to an element How to make a variable accessible outside a function? Hide Signs that Meteor.js was Used How to create a showdown.js markdown extension Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Summing radio input values How to execute an action before close metro app WinJS javascript, for loop defines a dynamic variable name Getting all files in directory with ajax

Examples related to html

Embed ruby within URL : Middleman Blog Please help me convert this script to a simple image slider Generating a list of pages (not posts) without the index file Why there is this "clear" class before footer? Is it possible to change the content HTML5 alert messages? Getting all files in directory with ajax DevTools failed to load SourceMap: Could not load content for chrome-extension How to set width of mat-table column in angular? How to open a link in new tab using angular? ERROR Error: Uncaught (in promise), Cannot match any routes. URL Segment

Examples related to ajax

Getting all files in directory with ajax Cross-Origin Read Blocking (CORB) Jquery AJAX: No 'Access-Control-Allow-Origin' header is present on the requested resource Fetch API request timeout? How do I post form data with fetch api? Ajax LARAVEL 419 POST error Laravel 5.5 ajax call 419 (unknown status) How to allow CORS in react.js? Angular 2: How to access an HTTP response body? How to post a file from a form with Axios

Examples related to file-upload

bootstrap 4 file input doesn't show the file name How to post a file from a form with Axios File Upload In Angular? How to set the max size of upload file The request was rejected because no multipart boundary was found in springboot Send multipart/form-data files with angular using $http File upload from <input type="file"> How to upload files in asp.net core? REST API - file (ie images) processing - best practices Angular - POST uploaded file