This will give you a full screen mode of both the apps, with a 50-50 split. You can drag the middle divider to re-adjust how much space you want for each app.
Code with your favourite code editor on one side, and preview the changes on the browser on the other side.
Next, hit the F3 key to go into Mission Control.
To put this into perspective, you can:
With your first app already open, click on the green button on the top left corner of the app to get it into fullscreen mode.
How to enable Split View in El Capitan
Or like what I personally often do – have the browser on one side, and Inspect Element on the other for code inspecting and debugging.
There is a video tutorial at the bottom of this post that you can skip to, but if your Internet connection leaves a lot to be desired, then here are the steps:
To exit split view, or remove one app from the split view so you can add another, just hit the Esc key or click the green button on the top left corner of the particular app to restore it to its original size.
How to exit Split View
One of the most anticipated feature in apple's latest os x, El Capitan is probably the Split View. This new feature allows you to focus on two apps simutaneously, side by side, without the distractions of any other apps you have opened on your Mac.
While inside Mission Control, drag the second app and release it into the thumbnail of the first app.