I loved howtocenterincss so I created an interactive version as a chrome extension.
One thing I noticed in the comments about the original was that there are many different choices for centering, based on browser compatibility and preference, so I’ve included different methods.
When you select the element you want centered, you’re presented with alternative methods based on the element and its context. Clicking a method lets you preview the change, explains how it works, and gives you the necessary source code changes.
When I have time I want to improve it/add more features, please let me know your suggestions in the comments :) Thanks!
