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:

<details>
	<summary><b>nodejs read a file</b> (click to show)</summary>

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

</details>

<details>
	<summary><b>Browser read TABLE element from page</b> (click to show)</summary>

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

</details>

<details>
	<summary><b>Browser download file (ajax)</b> (click to show)</summary>

Note: 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();
```

</details>

<details>
	<summary><b>Browser drag-and-drop</b> (click to show)</summary>

Drag-and-drop uses FileReader with 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);
```

</details>

<details>
	<summary><b>Browser file upload form element</b> (click to show)</summary>

```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);
```

</details>


### 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.

<details>
	<summary><b>Get base64 encoding on OSX / Windows</b> (click to show)</summary>

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)

</details>

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