Highlight and select phrases in HTML pages.
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


HTML Highlighter

CircleCI npm

The HTML Highlighter is a JavaScript module that solves these problems:

  1. Display colorful highlights on words in a live Web page that are determined by either or both of these sources:
    1. User selections identified by a user dragging their pointer over a portion of a page, possibly covering multiple tags in the DOM tree.
    2. Machine selections identified by a program, which might run in the browser or in a server-side environment that processes the HTML and text of a page to decide which portions of content should be marked.
  2. Provide these offsets to either JavaScript or backend tools. StreamCorpus Pipeline is being extended to provide translation between the relative offsets generated by HTML Highlighter and the absolute character offsets used by many backend text processing tools.
  3. Provide objects isomorphic to JavaScript's Range object, which has character offsets relative to DOM nodes identified by Xpaths:
    start: {
        xpath: <string> // unique address to DOM node
        offset: <int> // relative character offset
    end: {
        xpath: <string> // unique address to DOM node
        offset: <int> // relative character offset

The inline comments and class documentation are sufficient for a JavaScript programmer to jump in and start using this. To see an example, you can:

    $ git clone git://github.com/dossier/html-highlighter
    $ cd html-highlighter
    $ yarn install
    $ yarn start
    $ $BROWSER http://localhost:8080/examples/monolith/

Note the trailing slash in the URL fragment examples/monolith/. Omitting the slash will result in something loading but not quite running.


The HTML Highlighter library relies on a number of dependencies that must be installed before any other step is taken. Installing dependencies can be done as given below:

$ yarn install



When hacking on the HTML Highlighter, running the following command frees one from having to manually compile the code with each iteration. Bundles are automatically generated as changes are made, making development a breeze.

Generated assets can be accessed on a browser via the URL http://localhost:8080, however the port can be customized via the environment variable NODE_PORT.

$ yarn start

An alternative dynamic build mode relies on webpack's watch method for building bundles incrementally as changes are made. Assets are placed in the directory dist.

$ yarn start:watch

Finally, the command given below creates a static development build which is composed of a minified bundle of the HTML Highlighter library with the suffix .min.js added to distinguish it from the development build artifact. All artifacts are placed inside the dist directory and its existing contents are left untouched. Note that this command must be run each time changes are made to the code.

$ yarn build:min


Creating a production build requires running a simple command and results in only the HTML Highlighter library being built, fully optimized and minimized. Everything else is omitted.

$ yarn prepublish

Running tests

Running tests requires a standard terminal environment and can be accomplished by executing the following command:

$ yarn test

Note that tests relying on the document.createRange function are skipped due to the fact that jsdom, the virtual DOM environment used, does not provide an implementation.

Release process

To release this repository to NPM, we use the following command:

npm version <type>

Once that command has been run, execute the following command to push the new commit and its tag.

git push --follow-tags

The automated build in CircleCI will then publish the package to NPM.