How to debug obfuscated JavaScript?

Question

I need to debug obfuscated JavaScript like this example:

__d("DataStore",[],function(a,b,c,d,e,f){var g={},h=1;function i(l){if(typeof l=='string'){return 'str_'+l;}else return 'elem_'+(l.__FB_TOKEN||(l.__FB_TOKEN=[h++]))........

JavaScript debuggers embedded in MSIE, Opera and Chrome do not understand that JS uses semicolons and not CRLF as a line breaks; so it is impossible to debug a script like that, because entire function is located on one large line, and the debugger always highlights this one line disallowing me to see what part of code is actually executed.

Is there any way to debug JavaScript files that contain a very long line of code and don't use CRLF to separate code lines?

Community · Accepted Answer · 2013-09-30 15:00:58Z

36

The Chrome devtools "Scripts/Sources" pane has a "pretty print" mode (look for the {} button in the bottom toolbar).

edited Sep 30, 2013 at 15:00

CommunityBot

11 silver badge

answered Jun 7, 2012 at 12:50

lanzz

43.4k12 gold badges93 silver badges99 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Andrew Over a year ago

returned to frontend and completely forgot about this small icon. Thank you

user1427458 · Accepted Answer · 2012-06-07 12:52:26Z

3

Use a Javascript Beautifier to reformat the code and then debug the code.

Check out http://jsbeautifier.org/

answered Jun 7, 2012 at 12:52

user1427458

Comments

MaxArt · Accepted Answer · 2012-06-07 12:51:03Z

1

Google Chrome has a "Pretty print" function that allows to reindent the code.

I don't normally use it, so I don't know since when it exists, but it's present in Chrome 21 dev.

answered Jun 7, 2012 at 12:51

MaxArt

22.8k10 gold badges85 silver badges82 bronze badges

Comments

Jerome WAGNER · Accepted Answer · 2012-06-07 12:52:04Z

1

There is no single solution for this. The first thing you can to to have something a bit more readable is to copy/paste the javascript code into http://jsbeautifier.org/

answered Jun 7, 2012 at 12:52

Jerome WAGNER

22.6k10 gold badges64 silver badges79 bronze badges

1 Comment

Jerome WAGNER Over a year ago

not directly your chrome solution seems better if it works. But you can modify the script tag to load the beautified version and then debug it.

Collectives™ on Stack Overflow

How to debug obfuscated JavaScript?

4 Answers 4

1 Comment

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related