FileReader.readAsText()

The readAsText() method is used to read the contents of the specified Blob or File. When the read operation is complete, the readyState is changed to DONE, the loadend event is triggered, and the result property contains the contents of the file as a text string.

Syntax

readAsText(blob)
readAsText(blob, encoding)

Parameters

blob

The Blob or File from which to read.

encoding Optional

A string specifying the encoding to use for the returned data. By default, UTF-8 is assumed if this parameter is not specified.

Example

HTML

<input type="file" onchange="previewFile()"><br>
<p class="content"></p>

JavaScript

function previewFile() {
  const content = document.querySelector('.content');
  const [file] = document.querySelector('input[type=file]').files;
  const reader = new FileReader();

  reader.addEventListener("load", () => {
    // this will then display a text file
    content.innerText = reader.result;
  }, false);

  if (file) {
    reader.readAsText(file);
  }
}

Result

Specifications

Browser compatibility

See also

• FileReader