Barcode-scanner.JS is a Javascript library that provide implementation of Magnetic stripe/barcode USB and PS/2 scanners. It's detects when user use a magnetic stripe or barcode scanner, and call specific callbacks.

At the core Barcode-scanner.JS intercepts key press events and if they occur with high frequency stores them in buffer, and then analyzes and provides the developer with the processed result. As a bonus library hides the flow of events associated with the operation of the scanner using (hiding does not lead to loss of a single control and numeric chars - library repeated event and modify input elements text).

When using Barcode-scanner.JS you just have to define the event handler that should be called when scanner is been used (error and receive handler are not mandatory) to initialize library like:

scanner.oncomplete = function (data) {
  // Successful scanning
};
scanner.onerror = function (data) {
  // Unsuccessful scanning
};
scanner.onreceive = function (event) {
  // Receiving the next char during scanning
};

or

scanner (oncomplete, onerror, onreceive);

function oncomplete (data) { }
function onerror (data) { }
function onreceive (event) { }

Complete and error event handlers obtained decoded object data with the result of the scan:

• successful barcode scanning

  {
    raw: "5901234123457",     // Raw data
    barcode: {
      present: true,          // Barcode present mark
      valid: true,            // (reserved, always true) Barcode is valid
      code: "5901234123457",  // Barcode without any prefix of postfix
      type: ""                // (reserved, always empty string) Barcode type
    },
    magneticStripe: {
      present: false,
      valid: true,
      track1: "",
      track2: "",
      track3: ""
    }
  }

• successful magnetic stripe scanning

  {
    raw: "5901234123457",  // Raw data
    barcode: {
      present: false,
      valid: true,
      code: "",
      type: ""
    },
    magneticStripe: {
      present: true,       // Magnetic stripe present mark
      valid: true,         // Magnetic stripe is valid
      track1: "",          // Track #1 without any prefix of postfix if present
      track2: "",          // Track #2 without any prefix of postfix if present
      track3: ""           // Track #2 without any prefix of postfix if present
    }
  }

• unsuccessful scanning

  {
    error: new Error ("Error message"),  // Error description
    raw: "FOO",                          // Raw data
    barcode: {                           // Filling depends on scanning data and error severity
      present: false,
      valid: true,
      code: "",
      type: ""
    },
    magneticStripe: {                    // Filling depends on scanning data and error severity
      present: true,
      valid: false,
      track1: "",
      track2: "FOO",
      track3: ""
    }
  }

  Possible error messages:

  • Empty dataset
  • Dataset not recognized
  • Magnetics stripe: incorrect track #1
  • Magnetics stripe: incorrect track #2
  • Magnetics stripe: incorrect track #3
  • Magnetics stripe: unexpected data

Receive event handler obtained default key press event object event.

For fine-tune you can additionally config next properties of scanner:

• enabled {Boolean} - Scanner tracking enabling. Default: true.
• oncomplete {Function} - Successful scanning event (callback).
• onerror {Function} - Unsuccessful scanning event (callback).
• onreceive {Function} - Next char receiving event during scanning (callback).
• schema {Object} - Raw data decoding schema.
• sensitivity {Number} - Time (in ms) between two chars when user using scanner. Used to do track difference between keyboard typing and scanning. Default: 30 ms.
• preventDefault {Boolean} - Prevent default action on key press event. Default: true.
• stopPropagation {Boolean} - Immediately stop propagation on key press event. Default: true.

Library provides three ways for initialization:

• events only set

  scaner (oncomplete, [onerror], [onreceive])

  scanner (oncomplete, onerror, onreceive);
    
  function oncomplete (data) { }
  function onerror (data) { }
  function onreceive (event) { }

• events and DOM element tracking set

  scaner (target, [oncomplete], [onerror], [onreceive])

  where target is DOM element or jQuery object that will limit library in taking scanner. By default library taking scanner through window.

  target = $( "#order-form" );
  
  scanner (target, oncomplete, onerror, onreceive);
    
  function oncomplete (data) { }
  function onerror (data) { }
  function onreceive (event) { }

• options and DOM element tracking set

  scaner (options)

  schema = new scanner.Schema ();
  schema.barcode.startSentinel = ";";
  schema.barcode.endSentinel = "\\?";
  
  scanner ({
    target: $( "#order-form" ),
    oncomplete: oncomplete,
    onerror: onerror,
    onerror: onerror,
    schema: schema,
    sensitivity: 50,
    preventDefault: false,
    stopPropagation: false
  });
    
  function oncomplete (data) { }
  function onerror (data) { }
  function onreceive (event) { }

Method scanner.Decode allows analise and validate raw string contained barcode or magnetic stripe data. With default

data = new scanner.Decode ("%ALEXANDER_PEREVERZEV?");

or special analysing scheme

schema = new scanner.Schema ();
schema.barcode.startSentinel = ";";
schema.barcode.endSentinel = "\\?";

data = new scanner.Decode (";5901234123457?", schema);

Object created by scanner.Schema describing schema for decoding raw data. Default schema:

{
  barcode: {
    listen: true,                  // Barcode expected mark
    startSentinel: "",             // Beginning symbol
    endSentinel: "",               // Ending symbol
    LRC: "(?:(?:\\r\\n)|\\n|\\r)"  // Data set ending character
  },
  magneticStripe: {
    listen: true,                  // Magnetic stripe expected mark
    track1: {
      startSentinel: "%",          // I-track beginning symbol
      endSentinel: "\\?",          // I-track ending symbol
    },
    track2: {
      startSentinel: ";",          // II-track beginning symbol
      endSentinel: "\\?",          // II-track ending symbol
    },
    track3: {
      startSentinel: "_",          // III-track beginning symbol
      endSentinel: "\\?",          // III-track ending symbol
    },
    LRC: "(?:(?:\\r\\n)|\\n|\\r)"  // Traks and data set ending character
  }
}

Decoder validate magnetic stripe data based on accepted standarts:

• I-track:
  • valid characters: QWERTYUIOPASDFGHJKLZXCVBNM0123456789:;=+()–‘"!@#^&*<>/\
  • length: 76 symbols
  • line beginning: %
  • line ending: ?
• II-track:
  • valid characters: 0123456789=
  • length: 37 symbols
  • line beginning: ;
  • line ending: ?
• III-track:
  • valid characters: 0123456789=
  • length: 104 symbols
  • line beginning: _
  • line ending: ?

Barcode validation not supported yet :(

• Internet Explorer 7+
• Firefox 3+
• Opera 12+
• Safari
• Google Chrome

Barcode-scanner.JS is distributed under the MIT license. Please keep the existing headers.

Developer Alexander Pereverzev - [email protected]

Using borrowings from projects

• Textarea Cursor Position in Internet Explorer - (C) 2006 Jake Roberts
• crossBrowser_initKeyboardEvent.js - (C) 2013 Егор Халимоненко