What does 'Error: uncaught exception: Syntax error, unrecognized expression: [object Object]' mean in jQuery?

I keep getting this error:

Error: uncaught exception: Syntax error, unrecognized expression: [object Object]

There is no line number or anything associated with it. It comes fr开发者_如何转开发om this script: http://www.fissiondesigns.com/simon/. Try drawing a square on the picture to reproduce.

What does the error mean and how do I prevent it?

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Script you are using has some kind of parser. It should have sth like this:

throw "Syntax error, unrecognized expression: " + object.toString()

where object is some json instead of string in your case. I would check the configuration options for widget you are using.

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Whilst in dev/debug it helps not to use the minified versions of js libraries as you tend to get nonsensical errors.

Try including the full jquery/ui versions first to get better error info.

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Have you tried it with jQuery 1.4.2 + jQuery UI 1.8.2? It's a general law of computer science: always use the latest version. Bugs age getting fixed, design flaws are getting cleared up, etc.