You can preview an article, product, event or form at any time by clicking on the Preview button.  It is not necessary to Save before using Preview.  

In Preview mode, a new tab will open and this orange box will appear at the top.  You cannot edit from this view, but you will be able to see how the article, product, event or form looks, even if it is not Active.

After you view your preview, close the tab and click back to the article edit screen to make revisions.

NOTE:  If you edit the article, close the Preview tab and click Preview again.  You cannot refresh Preview Mode.