FileReader: readAsText() method - Web APIs | MDN

Syntax

js

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.

Return value

None (undefined).

Examples

HTML

html

<input type="file" /><br />
<p class="content"></p>

JavaScript

js

const content = document.querySelector(".content");
const fileInput = document.querySelector("input[type=file]");

fileInput.addEventListener("change", previewFile);

function previewFile() {
  const file = fileInput.files[0];
  const reader = new FileReader();

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

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

Result

Specifications

Specification
File API
# readAsDataText

Browser compatibility

See also

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