On Sublime Text you can visualize a tab (as a line), and space (as a dot) - as per this StackOverflow forum.
Please is there something similar for the Cloud9 IDE?
e.g.
Many thanks!
In order to view invisible characters within the Cloud9 Editor, please visit the preferences panel (Cloud9 > Preferences), then click on User Settings, and then Code Editor (Ace) within Editors. Enable 'Show Invisible Characters' and you should be all set.