Dev Depo: CodePen.IO, Interactive Coding Platform

A warning to coders: we apologize in advance for the number of hours you’ll spend at CodePen (www.codepen.io), an interactive coding platform that allows users to “instantly build, explore and teach the web,” but rest assured, it will be time well spent: as CodePen not only enables you to post HTML, CSS and JavaScript snippets in job-winning coding examples known as “Pens,” but to modify the structure of existing Pens submitted by other users — viewing the results of the code modifications in a real-time preview pane.

According to its publishers, CodePen is a playground for the frontend side of the web that is all about inspiration, education and sharing. It is ideally suited to building reduced test cases to demonstrate and to figure out bugs — and to show off your latest creations while receiving valuable feedback from your peers. CodePen also allows users to locate examples of a particular design pattern and more. A pro version adds features such as a Collab Mode that allows users to pair program in real-time, plus a Professor Mode for allowing a group of students to follow your teaching examples while chatting together.

CodePen is a playground for the frontend side of the web that is all about inspiration, education and sharing.

With CodePen the possibilities are endless and the results are pretty impressive.

Using this tool is straightforward and begins when you click on “New Pen,” which then opens up three blank windows for you to copy and paste your HTML, CSS and any JavaScript coding into. The system perhaps works best when using it to display specific elements, such as a Flash-less 3D rotating menu item executed exclusively in HTML5.

Custom options are selectable for each of these panes via the Gear icon. For example, the HTML tab has toggles for HAML, Markdown and Slim preprocessors, as well as the option of adding custom head code and HTML tag classes. The CSS panel offers support for SASS and SCSS (both with Compass) as well as Less and a toggle for CSS prefixing. External CSS files can be added, as can Normalize and Reset for cross-browser stability.

The JavaScript pane enables custom options including external JavaScript files and the ability to specify libraries such as Dojo, Ext JS, jQuery and jQuery UI, MooTools, Prototype, YUI and Zepto. A toggle for Modernizr support is also provided.

CodePen doesn’t import any assets, so if you want to use external JavaScript files or other remotely hosted resources, then ensure that absolute links are used — since relative links will not function in the live browser preview.

Full Page and Live View URLs allow easy sharing of comps, while CodePen itself is accessible by anyone running Chrome 1+, Firefox 4+, IE 9+, Opera 11+ and Safari 4+, with enhanced support for mobile devices an important feature that the company says it’s working on for a future CodePen upgrade.

Altogether, CodePen may be hard to explain but is easy to understand in practice. Give it a try and see if you can learn something from the work of top coders — or show them up with a binary masterpiece of your own.

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