xsheetjs/docbits/20_import.md

## 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:

```js
if(typeof require !== 'undefined') XLSX = require('xlsx');
var workbook = XLSX.readFile('test.xlsx');
/* DO SOMETHING WITH workbook HERE */
```

- Browser DOM Table element:

```js
var worksheet = XLSX.utils.table_to_book(document.getElementById('tableau'));
/* DO SOMETHING WITH workbook HERE */
```

- ajax (for a more complete example that works in older browsers, check the demo
  at <http://oss.sheetjs.com/js-xlsx/ajax.html>):

```js
/* set up XMLHttpRequest */
var url = "test_files/formula_stress_test_ajax.xlsx";
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 XLSX */
  var workbook = XLSX.read(bstr, {type:"binary"});

  /* DO SOMETHING WITH workbook HERE */
}

oReq.send();
```

- HTML5 drag-and-drop using readAsBinaryString or readAsArrayBuffer:
  note: readAsBinaryString and readAsArrayBuffer may not be available in every
  browser.  Use dynamic feature tests to determine which method to use.

```js
/* processing array buffers, only required for readAsArrayBuffer */
function fixdata(data) {
  var o = "", l = 0, w = 10240;
  for(; l<data.byteLength/w; ++l) o+=String.fromCharCode.apply(null,new Uint8Array(data.slice(l*w,l*w+w)));
  o+=String.fromCharCode.apply(null, new Uint8Array(data.slice(l*w)));
  return o;
}

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

      var workbook;
      if(rABS) {
        /* if binary string, read with type 'binary' */
        workbook = XLSX.read(data, {type: 'binary'});
      } else {
        /* if array buffer, convert to base64 */
        var arr = fixdata(data);
        workbook = XLSX.read(btoa(arr), {type: 'base64'});
      }

      /* DO SOMETHING WITH workbook HERE */
    };
    if(rABS) reader.readAsBinaryString(f);
    else reader.readAsArrayBuffer(f);
  }
}
drop_dom_element.addEventListener('drop', handleDrop, false);
```

- HTML5 input file element using readAsBinaryString or readAsArrayBuffer:

```js
/* fixdata and rABS are defined in the drag and drop example */
function handleFile(e) {
  var files = e.target.files;
  var i,f;
  for (i = 0; i != files.length; ++i) {
    f = files[i];
    var reader = new FileReader();
    var name = f.name;
    reader.onload = function(e) {
      var data = e.target.result;

      var workbook;
      if(rABS) {
        /* if binary string, read with type 'binary' */
        workbook = XLSX.read(data, {type: 'binary'});
      } else {
        /* if array buffer, convert to base64 */
        var arr = fixdata(data);
        workbook = XLSX.read(btoa(arr), {type: 'base64'});
      }

      /* DO SOMETHING WITH workbook HERE */
    };
    reader.readAsBinaryString(f);
  }
}
input_dom_element.addEventListener('change', handleFile, false);
```

**Complete examples:**

- <http://oss.sheetjs.com/js-xlsx/> HTML5 File API / Base64 Text / Web Workers

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

```bash
$ <target_file base64 | pbcopy
```

On Windows XP and up you can get the base64 encoding using `certutil`:

```cmd
> certutil -encode target_file target_file.b64
```

(note: You have to open the file and remove the header and footer lines)

- <http://oss.sheetjs.com/js-xlsx/ajax.html> XMLHttpRequest