Security / Protecting code in JavaScript

With all the recent hype about JavaScript and HTML5 replacing Flash, I wanted to know - How would it be possible to protect client-side js code? Of course, it is possibl开发者_如何学编程e to obfuscate it, but that would only make it a little harder. Also, for games which submit high scores to the server, wouldn't it be incredibly easy to modify those scores before they are sent to the server? I know even Flash files can be decompiled, but they can be obfuscated and flash decompilation is not as easy as modifying data in JS - could be done easily using a plugin such as Firebug. I'd like to know everyone's views on this.

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Javascript, being parsed on the client, is never 100% safe. There will always be ways to find out what it does. A few days ago I've even seen a tool which unpacks packed javascript so the only thing you can really do is using "ugly" variable names (or actually, make a javascript packer transform your "good" variable names into short/ugly/nonsense ones)

To protect game results, you have to move some of the game logic to the server so the client cannot send arbitrary results.

Summarizing it: Don't put secrets in javascript code and don't trust anything coming from the client - no matter if it's from a form or generated/submitted via javascript.

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You say that for game that sends high scores to the server it would be too easy to modify javascript and forge request?

Except for case, when you use some cryptography on the client, it is the easiest way to forge such request not even analysing the script but sending false request itself. Everything you send between server and browser can be easily viewed on computer, analysed and changed.