Thanks for taking the time to contribute to the jQuery project by writing a bug report.

This isn't a bug. Escaping single quotes inside a JSON string is neither needed or is it a valid thing to do.

You can easily verify that by:

• trying {"Text":"Sample \\'1\\'"} on http://www.jsonlint.com
• checking the definition of JSON Strings at http://json.org/ where all characters are listed that need to be escaped with a backslash

Someone else had the same issue: http://social.technet.microsoft.com/Forums/en-US/sharepoint2010programming/thread/49136617-0a2a-4963-9e4e-6181c60ec840?prof=required

In version 1.5 this can be fixed in line 56 of jQuery-1.5.js

	rvalidescape = /\\\\(?:['"\\\\\\/bfnrt]|u[0-9a-fA-F]{4})/g,

Perhaps this is NOT a bug in jQuery, but that's how Microsoft escapes single quotes so this info could prove to be useful to many developers using WFC Services.

Replying to [comment:2 pitus]:

Someone else had the same issue: http://social.technet.microsoft.com/Forums/en-US/sharepoint2010programming/thread/49136617-0a2a-4963-9e4e-6181c60ec840?prof=required In version 1.5 this can be fixed in line 56 of jQuery-1.5.js

> 	rvalidescape = /\\\\(?:['"\\\\\\/bfnrt]|u[0-9a-fA-F]{4})/g,
> 

Perhaps this is NOT a bug in jQuery, but that's how Microsoft escapes single quotes so this info could prove to be useful to many developers using WFC Services.

Are you really considering using a modified version of jQuery on a production side? That's not a good idea and will cause problems later on (upgrading, maintenance, unexpected behaviors, ...)

Instead I suggest you file this as a bug to the Microsoft WCF Data Service Team. And in the mean time use a new functionality available in jQuery 1.5 to workaround this problem. Use a custom json converter.

$.ajaxSetup({
    // use custom converter to handle invalid json data
    // returned by WCF Data Service
    // fixes invalid escaped single quotes (\\') in json data
    // e.g. { "foo": "bar\\'tender" } --> { "foo": "bar'tender" }
    converters: {
        "text json": function( textValue ) {
            return jQuery.parseJSON( textValue.replace(/(^|[^\\\\])\\\\'/g, "$1'") );
        }
    }
});

Thanks for the converters example. I ended up using a slightly different version of it, one that also handles Microsoft Dates. Note that it doesn't handle Time Zone suffixes properly, as in Date(#-005)

$.ajaxSetup({
    // use custom converter to handle invalid json data returned by WCF Data Service
    // ignores invalid escaped single quotes (\\') in json data
    //     e.g. { "foo": "bar\\'tender" } --> { "foo": "bar'tender" }
    // also converts Microsoft Dates into actual Date objects
    //     e.g. { "\\/Date(###)\\/" } --> { new Date(###) }
    converters: {
        "text json": function (textValue)
        {
            return (new Function("return " + textValue
                .replace(/"\\\\\\/Date\\((-?\\d*)\\)\\\\\\/"/g, "new Date($1)")
            ))();
        }
    }
});

That date converter should not be applied to "text json" since it will cause any resulting json results to be parsed into a Date or string or throw an exception rather than a nested object, which is the job of mime type "application/json" aka "text json".

What you're doing here is fine and all, but you might want to apply them to "* text" instead, and control the mime type of your response, or specify it with your call to $.ajax. Finally I'd suggest you add ^ and $ to your regex to avoid it throwing errors when your textValue contains a date as well as something else.

For a more involved discussion of how to deal with dates, feel free to have a look at this ticket: http://bugs.jquery.com/ticket/8671