Vorlon.js: Focus on DOM Explorer

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This article is part of a web development series from Microsoft. Thank you for supporting the partners who make SitePoint possible.

In April 2015, our team of engineers and tech evangelists at Microsoft released vorlon.js – an open source, extensible, platform-agnostic tool for remotely debugging and testing your JavaScript. This article is the first in a series that will take a detailed look at one specific feature, starting with one of the biggest: the DOM Explorer.


If you’re not familiar with vorlon.js, I recommend first reading this blog post, which explains why we made vorlon.js and how to use it. You’ll find additional vorlon.js information at the end of this article.

The DOM inspector shows you the DOM of the remote webpage. You can inspect the DOM, clicking on nodes will highlight them in the host webpage, and if you select one you can also view and modify its CSS properties.

DOM explorer

Installing Vorlon.js

Just as a reminder, here is what you have to do to use Vorlon.js:

  • Install and run the Vorlon.JS server from npm:
    $ npm i -g vorlon
    $ vorlon
  • Once Vorlon.js is done installing, you can now run the server:
    $ vorlon
    The Vorlon server is running
  • With the server is running, open http://localhost:1337 in your browser to see the Vorlon.js dashboard.
  • The last step is to enable Vorlon.js by adding this script tag to your app:
<script src="http://localhost:1337/vorlon.js"></script>

Now when you open your app you should see your client appear on the dashboard.

Using the DOM Explorer

By default, the DOM explorer is on but if you need to enable it, you have to go to [Vorlon folder]\Server\config.json and enable the plugin:

    "useSSL": false,
    "includeSocketIO": true,
    "activateAuth": false,
    "username": "",
    "password": "",
    "plugins": [
        { "id": "DOM", "name": "Dom Explorer", "panel": "top", "foldername": "domExplorer", "enabled": true }

Once enabled you will be able to control almost everything related to the DOM through plugin’s main window.

Using DOM explorer

And here is what you’ll be able to do:

Selection overlay

By moving your mouse over any node, you will be able to see where this node belongs on the client side:

Selection Overlay

Live text editing

By double-clicking on any text inside the DOM explorer window, you have the ability to live edit it:

Live text editing

But you can also use the HTML section on the right pane to edit HTML text content:

Live text editing console

This feature can also be reached by right-clicking on the node itself.

Attributes edition

Nodes’ attributes are also editable by just clicking on them:

Attributes edition

But you can also right click on the node name itself to add a new attribute:

Attributes edition

By right-clicking on existing attribute, you will get even more options like updating value or name or deleting the attribute:

Attributes edition

Search using CSS selector

When dealing with big HTML pages you may want to search a specific node. This is why we introduced the “search node by CSS selector” feature.

Just enter your selector in the search box and you’re done!

Search using CSS selector

Dynamic refresh

The DOM Explorer window can either be automatically refreshed when client DOM changes (beware as this could consume a lot of CPU power and network bandwidth even if we use delta updates) or can be refreshed on demand.

Auto refresh in controlled on the settings pane:

Dynamic refresh

When auto refresh is off, the Refresh button can tell you if there are available updates on the client side (The little dot on the button will turn red):

Refresh button

In this case, just clicking on the button will launch a complete refresh of the page

Styles editor

When you click on a node, the Styles pane will present you all the styles explicitly defined for this node:

Styles editor

You can then use the “+” button to add new style or click on existing ones to change their value:

Styles editor

To see ALL styles applied to a node (including implicit ones), you just have to use the Computed Styles pane:

Styles editor computed styles


Like browsers’ F12 tools, the Layout pane is here to help you understand the layout of every node that you select:

Layout pane

Link with Interactive console plugin

Finally, last one thing that you can find useful: When a node has an ID, you can click on the little button on the right of the node to have it linked directly in the interactive console where you will be able to execute the code you want with it:

Link interactive console plugin

Going further

That’s a lot of feature for a single plugin. I hope it will help you debug and fix your remote sites or web apps!

If you are interested by going further with Vorlon.js, you may find these articles interesting:

We are also looking for more contributors to help us creating the most useful tool possible. So if you are interested in contributing, please visit our GitHub repository.

More hands-on with JavaScript

This article is part of the web development series from Microsoft tech evangelists on practical JavaScript learning, open source projects, and interoperability best practices including Microsoft Edge browser and the new EdgeHTML rendering engine.

We encourage you to test across browsers and devices including Microsoft Edge – the default browser for Windows 10 – with free tools on dev.modern.IE:

In-depth tech learning on Microsoft Edge and the Web Platform from our engineers and evangelists:

More free cross-platform tools & resources for the Web Platform:

David CatuheDavid Catuhe
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David Catuhe is a Principal Program Manager at Microsoft focusing on web development. He is author of the babylon.js framework for building 3D games with HTML5 and WebGL. Read his blog on MSDN or follow him on Twitter.

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