Event tracking on websites
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Event tracking on websites using plain old JavaScript. No third-party libraries or external dependencies. 😃


  • For web pages: Just add load.min.js to your page (e.g. inside <head> element or right before the closing </body> tag) and configure tracking options.

  • For browser extensions: Add tracklib.min.js and trackui.min.js (in this order) to your manifest.json (or similar) and configure tracking options.

Example 1

Default configuration. Capture any browser event whenever it happens.

<script src="/path/to/load.min.js"></script>

    // Remember to point to save.php (or similar) to write the log files.
    postServer: "/path/to/save.php"


Example 2

Capture all mouse clicks whenever they happen. Also capture every mouse movement at 50 ms. All other browser events are ignored.

<script src="/path/to/load.min.js"></script>

    postServer: "/path/to/save.php",
    regularEvents: "click",
    pollingEvents: "mousemove",
    pollingMs: 50,


Example 3

Capture any browser event every 500 ms.

<script src="/path/to/load.min.js"></script>

    postServer: "/path/to/save.php",
    regularEvents: "",
    pollingEvents: "*",
    pollingMs: 500,


Example 4

Use the default settings within a Chrome extension:

  1. Add the following snippet to your manifest.json file:
"content_scripts": [{
  "js": [
  1. Add TrackUI.record(settings) in main.js, where settings holds your tracking options.

Default tracking settings

The settings object has the following defaults:

  // The server where logs will be stored.
  postServer: "//my.server.org/save.script",
  // The interval (in seconds) to post data to the server.
  postInterval: 30,
  // Events to be tracked whenever the browser fires them. Default:
  //      mouse-related: "mousedown mouseup mousemove mouseover mouseout mousewheel click dblclick"
  //      touch-related: "touchstart touchend touchmove"
  //   keyboard-related: "keydown keyup keypress"
  //     window-related: "load unload beforeunload blur focus resize error online offline"
  //             others: "scroll change select submit reset contextmenu cut copy paste"
  // If this property is empty, no events will be tracked.
  // Use space-separated values to indicate multiple events, e.g. "click mousemove touchmove".
  // The "*" wildcard can be used to specify all events.
  regularEvents: "*",
  // Events to be polled, because some events are not always needed (e.g. mousemove).
  // If this property is empty (default value), no events will be polled.
  // Use space-separated values to indicate multiple events, e.g. "mousemove touchmove".
  // The "*" wildcard can be used to specify all events.
  // Events in pollingEvents will override those specified in regularEvents.
  // You can leave regularEvents empty and use only pollingEvents, if need be.
  pollingEvents: "",
  // Sampling frequency (in ms) to register events.
  // If set to 0, every single event will be recorded.
  pollingMs: 150,
  // A name that identifies the current task.
  // Useful to filter logs by e.g. tracking campaign ID.
  taskName: "evtrack",
  // A custom function to execute on each recording tick.
  callback: null,
  // Whether to dump element attributes together with each recorded event.
  saveAttributes: true,
  // Enable this to display some debug information
  debug: false


For each browsed page, you'll have in the logs directory the following files:

  1. A space-delimited CSV-like file with 8 columns.
  2. An XML file with some metadata.

CSV file example

cursor timestamp xpos ypos event xpath attrs extras
0 1405503114382 0 0 load / {}


  • The cursor column indicates the cursor ID. Will be 0 for a regular computer mouse, or an integer indicating the finger ID for touch-capable browsers.
  • The timestamp column indicates the timestamp of the event, with millisecond precision.
  • The xpos and ypos columns indicate the x and y position of the cursor, respectively. For events that do not relate to any mouse event (e.g. load or blur), these values will be 0.
  • The event column indicates the browser's event name.
  • The xpath column indicates the target element that relates to the event, in XPath notation.
  • The attrs column indicates the element attributes, if any.
  • The extras column is populated with the result of the callback setting you've set.

XML file example

<?xml version="1.0" encoding="UTF-8"?>
 <date>Wed, 16 Jul 2014 11:32:24 +0200</date>
 <ua>Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.153 Safari/537.36</ua>

The <task /> element is the value you've set in the taskName setting. This is useful to annotate a particular tracking campaign's ID, an experimental user group, etc.


If you use this software in any academic project, please cite it as:

  • Leiva, L.A. and Vivó, R. Web Browsing Behavior Analysis and Interactive Hypervideo. ACM Transactions on the Web 7(4), 2013.
 author   = {Luis A. Leiva and Roberto Viv\'o},
 title    = {Web Browsing Behavior Analysis and Interactive Hypervideo},
 journal  = {ACM Transactions on the Web},
 volume   = {7},
 number   = {4},
 year     = {2013},


This software is dual-licensed under the MIT and LGPL v3 licenses. See the license dir.