Excel 5.0/95 and 97-2004 spreadsheet (BIFF5 XLS / BIFF8 XLS / XML 2003) parser (forked)

excel, xls, office, spreadsheet
npm install xlsjs2@0.7.5


NOTE: this project has been merged into js-xlsx. The API is identical to js-xls. Some future changes may be backported, but all new projects should use js-xlsx.


Parser for Excel XLS (BIFF5/BIFF8) and 2003-2004 (XML) files. Pure-JS cleanroom implementation from the Microsoft Open Specifications and related documents.

Demo: http://oss.sheetjs.com/js-xls

Source: http://sheetjs.com/js-xls


With npm:

npm install xlsjs

In the browser:

<script lang="javascript" src="xls.js"></script>

With bower:

bower install js-xls

CDNjs automatically pulls the latest version and makes all versions available at http://cdnjs.com/libraries/xls

Optional Modules

The node version automatically requires modules for additional features. Some of these modules are rather large in size and are only needed in special circumstances, so they do not ship with the core. For browser use, they must be included directly:

<!-- international support from https://github.com/sheetjs/js-codepage -->
<script src="dist/cpexcel.js"></script>

An appropriate version for each dependency is included in the dist/ directory.

The complete single-file version is generated at dist/xls.full.min.js

ECMAScript 5 Compatibility

Since xls.js uses ES5 functions like Array#forEach, older browsers require Polyfills. This repo and the gh-pages branch include a shim

To use the shim, add the shim before the script tag that loads xls.js:

<script type="text/javascript" src="/path/to/shim.js"></script>

Parsing Workbooks

For parsing, the first step is to read the file. This involves acquiring the data and feeding it into the library. Here are a few common scenarios:

  • node readFile:
if(typeof require !== 'undefined') XLS = require('xlsjs');
var workbook = XLS.readFile('test.xls');
/* set up XMLHttpRequest */
var url = "test_files/formula_stress_test_ajax.xls";
var oReq = new XMLHttpRequest();
oReq.open("GET", url, true);
oReq.responseType = "arraybuffer";

oReq.onload = function(e) {
  var arraybuffer = oReq.response;

  /* convert data to binary string */
  var data = new Uint8Array(arraybuffer);
  var arr = new Array();
  for(var i = 0; i != data.length; ++i) arr[i] = String.fromCharCode(data[i]);
  var bstr = arr.join("");

  /* Call XLS */
  var workbook = XLS.read(bstr, {type:"binary"});

  /* DO SOMETHING WITH workbook HERE */

  • HTML5 drag-and-drop using readAsBinaryString:
/* set up drag-and-drop event */
function handleDrop(e) {
  var files = e.dataTransfer.files;
  var i,f;
  for (i = 0, f = files[i]; i != files.length; ++i) {
    var reader = new FileReader();
    var name = f.name;
    reader.onload = function(e) {
      var data = e.target.result;

      /* if binary string, read with type 'binary' */
      var workbook = XLS.read(data, {type: 'binary'});

      /* DO SOMETHING WITH workbook HERE */
drop_dom_element.addEventListener('drop', handleDrop, false);

Working with the Workbook

This example gets the value of cell A1 of the first worksheet:

var sheet_name_list = workbook.SheetNames;
var Sheet1A1 = workbook.Sheets[sheet_name_list[0]]['A1'].v;

Complete examples:

Note that older versions of IE does not support HTML5 File API, so the base64 mode is provided for testing. On OSX you can get the base64 encoding with:

$ <target_file.xls base64 | pbcopy

The node version installs a binary xls which can read XLS and XML2003 files and output the contents in various formats. The source is available at xls.njs in the bin directory.

Some helper functions in XLS.utils generate different views of the sheets:

  • XLS.utils.sheet_to_csv generates CSV
  • XLS.utils.sheet_to_json generates an array of objects
  • XLS.utils.get_formulae generates a list of formulae


XLS is the exposed variable in the browser and the exported node variable

XLS.version is the version of the library (added by the build script).

XLS.SSF is an embedded version of the format library.

Parsing functions

XLS.read(data, read_opts) attempts to parse data.

XLS.readFile(filename, read_opts) attempts to read filename and parse.


Utilities are available in the XLS.utils object:


  • sheet_to_json converts a workbook object to an array of JSON objects.
  • sheet_to_csv generates delimiter-separated-values output
  • sheet_to_formulae generates a list of the formulae (with value fallbacks)

Cell and cell address manipulation:

  • format_cell generates the text value for a cell (using number formats)
  • {en,de}code_{row,col} convert between 0-indexed rows/cols and A1 forms.
  • {en,de}code_cell converts cell addresses
  • {en,de}code_range converts cell ranges

Workbook / Worksheet / Cell Object Description

js-xls conforms to the Common Spreadsheet Format (CSF):

General Structures

Cell address objects are stored as {c:C, r:R} where C and R are 0-indexed column and row numbers, respectively. For example, the cell address B5 is represented by the object {c:1, r:4}.

Cell range objects are stored as {s:S, e:E} where S is the first cell and E is the last cell in the range. The ranges are inclusive. For example, the range A3:B7 is represented by the object {s:{c:0, r:2}, e:{c:1, r:6}}. Utils use the following pattern to walk each of the cells in a range:

for(var R = range.s.r; R <= range.e.r; ++R) {
  for(var C = range.s.c; C <= range.e.c; ++C) {
    var cell_address = {c:C, r:R};

Cell Object

Key Description
v raw value (see Data Types section for more info)
w formatted text (if applicable)
t cell type: b Boolean, n Number, e error, s String, d Date
f cell formula (if applicable)
z number format string associated with the cell (if requested)
s the style/theme of the cell (if applicable)

Built-in export utilities (such as the CSV exporter) will use the w text if it is available. To change a value, be sure to delete cell.w (or set it to undefined) before attempting to export. The utilities will regenerate the w text from the number format (cell.z) and the raw value if possible.

Data Types

The raw value is stored in the v field, interpreted based on the t field.

Type b is the Boolean type. v is interpreted according to JS truth tables

Type e is the Error type. v holds the number and w holds the common name:

Value Error Meaning
0x00 #NULL!
0x07 #DIV/0!
0x0F #VALUE!
0x17 #REF!
0x1D #NAME?
0x24 #NUM!
0x2A #N/A

Type n is the Number type. This includes all forms of data that Excel stores as numbers, such as dates/times and Boolean fields. Excel exclusively uses data that can be fit in an IEEE754 floating point number, just like JS Number, so the v field holds the raw number. The w field holds formatted text.

Type s is the String type. v should be explicitly stored as a string to avoid possible confusion.

Worksheet Object

Each key that does not start with ! maps to a cell (using A-1 notation)

worksheet[address] returns the cell object for the specified address.

Special worksheet keys (accessible as worksheet[key], each starting with !):

  • ws['!ref']: A-1 based range representing the worksheet range. Functions that work with sheets should use this parameter to determine the range. Cells that are assigned outside of the range are not processed. In particular, when writing a worksheet by hand, be sure to update the range. For a longer discussion, see http://git.io/KIaNKQ

    Functions that handle worksheets should test for the presence of !ref field. If the !ref is omitted or is not a valid range, functions are free to treat the sheet as empty or attempt to guess the range. The standard utilities that ship with this library treat sheets as empty (for example, the CSV output is an empty string).

  • ws['!merges']: array of range objects corresponding to the merged cells in the worksheet. Plaintext utilities are unaware of merge cells. CSV export will write all cells in the merge range if they exist, so be sure that only the first cell (upper-left) in the range is set.

Workbook Object

workbook.SheetNames is an ordered list of the sheets in the workbook

wb.Sheets[sheetname] returns an object representing the worksheet.

wb.Props is an object storing the standard properties. wb.Custprops stores custom properties. Since the XLS standard properties deviate from the XLSX standard, both objects are identical.

Parsing Options

The exported read and readFile functions accept an options argument:

Option Name Default Description
cellFormula true Save formulae to the .f field **
cellNF false Save number format string to the .z field
cellStyles false Save style/theme info to the .s field
sheetRows 0 If >0, read the first sheetRows rows **
bookFiles false If true, add raw files to book object **
bookProps false If true, only parse enough to get book metadata **
bookSheets false If true, only parse enough to get the sheet names
password "" If defined and file is encrypted, use password **
  • cellFormula only applies to constructing XLS formulae. XLML R1C1 formulae are stored in plaintext, but XLS formulae are stored in a binary format.
  • Even if cellNF is false, formatted text will be generated and saved to .w
  • In some cases, sheets may be parsed even if bookSheets is false.
  • bookSheets and bookProps combine to give both sets of information
  • bookFiles adds a cfb object (XLS only)
  • sheetRows-1 rows will be generated when looking at the JSON object output (since the header row is counted as a row when parsing the data)
  • Currently only XOR encryption is supported. Unsupported error will be thrown for files employing other encryption methods.

Tested Environments

  • NodeJS 0.8, 0.10 (latest release), 0.11.14 (unstable), io.js
  • IE 6/7/8/9/10/11 using Base64 mode (IE10/11 using HTML5 mode)
  • FF 18 using Base64 or HTML5 mode
  • Chrome 24 using Base64 or HTML5 mode

Tests utilize the mocha testing framework. Travis-CI and Sauce Labs links:

Test Files

Test files are housed in another repo.

Running make init will refresh the test_files submodule and get the files.


make test will run the node-based tests. To run the in-browser tests, clone the oss.sheetjs.com repo and replace the xls.js file (then fire up the browser and go to stress.html):

$ cp xls.js ../SheetJS.github.io
$ cd ../SheetJS.github.io
$ simplehttpserver # or "python -mSimpleHTTPServer" or "serve"
$ open -a Chromium.app http://localhost:8000/stress.html

For a much smaller test, run make test_misc.


Due to the precarious nature of the Open Specifications Promise, it is very important to ensure code is cleanroom. Consult CONTRIBUTING.md

The xls.js file is constructed from the files in the bits subdirectory. The build script (run make) will concatenate the individual bits to produce the script. Before submitting a contribution, ensure that running make will produce the xls.js file exactly. The simplest way to test is to move the script:

$ mv xls.js xls.new.js
$ make
$ diff xls.js xls.new.js

To produce the dist files, run make dist. The dist files are updated in each version release and should not be committed between versions.


XLSX/XLSM/XLSB/ODS is available in js-xlsx.


Please consult the attached LICENSE file for details. All rights not explicitly granted by the Apache 2.0 license are reserved by the Original Author.

It is the opinion of the Original Author that this code conforms to the terms of the Microsoft Open Specifications Promise, falling under the same terms as OpenOffice (which is governed by the Apache License v2). Given the vagaries of the promise, the Original Author makes no legal claim that in fact end users are protected from future actions. It is highly recommended that, for commercial uses, you consult a lawyer before proceeding.


Certain features are shared with the Office Open XML File Formats, covered in:

ISO/IEC 29500:2012(E) "Information technology — Document description and processing languages — Office Open XML File Formats"

OSP-covered specifications:

  • [MS-CFB]: Compound File Binary File Format
  • [MS-XLS]: Excel Binary File Format (.xls) Structure Specification
  • [MS-XLSB]: Excel (.xlsb) Binary File Format
  • [MS-XLSX]: Excel (.xlsx) Extensions to the Office Open XML SpreadsheetML File Format
  • [MS-ODATA]: Open Data Protocol (OData)
  • [MS-OFFCRYPTO]: Office Document Cryptography Structure
  • [MS-OLEDS]: Object Linking and Embedding (OLE) Data Structures
  • [MS-OLEPS]: Object Linking and Embedding (OLE) Property Set Data Structures
  • [MS-OSHARED]: Office Common Data Types and Objects Structures
  • [MS-OVBA]: Office VBA File Format Structure
  • [MS-OE376]: Office Implementation Information for ECMA-376 Standards Support
  • [MS-CTXLS]: Excel Custom Toolbar Binary File Format
  • [MS-XLDM]: Spreadsheet Data Model File Format
  • [MS-EXSPXML3]: Excel Calculation Version 2 Web Service XML Schema
  • [XLS]: Microsoft Office Excel 97-2007 Binary File Format Specification


Build Status

Coverage Status

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