Parsing JSON with Javascript

Don't use eval: use a proper JSON parser such as JSON2.

You probably have extra content in the response: check that you are not printing anything else out.

This is working for me:

JSON.parse('{ "status" : "OK", "addresses" : [0,1,2,3,4,5]}');

If you want to use eval, then you need to use the second example you posted ({"status":"OK","addresses":[0,1,2,3,4,5]}) and you need to surround the string with parenthesis as such:

var jsonObj = eval( '('+jsonString+')' );

This makes jsonString a valid javascript statement.

With that being said, I encourage you use JSON.parse, as many others have posted. It is far more secure.

You don't have a JSON string. You do have an object literal. You need the names to have quotes.

{"status":OK, "addresses":[0,1,2,3,4,5]}

Based on this comment:

So I verified that when JSon is received from the request, all the " are replaced by " ... could this be the problem?

Yes. A JSON parser expects to receive JSON as input, not HTML encoded JSON.

Two issues to fix:

1. Add quotes around the "OK" to make it a legal javascript string.
2. Add parens around the string before sending to eval like this eval("(" + jsonString + ")")';

This:

{status:OK,addresses:[0,1,2,3,4,5]}

would have to be changed to this:

{status:"OK",addresses:[0,1,2,3,4,5]}

to be valid Javascript (note the quotes around "OK").

It should be this to be valid JSON (quotes around the keys too):

{"status":"OK", "addresses":[0,1,2,3,4,5]}

OK all by itself is not a known piece of Javascript without the quotes around it to make it into a Javascript string. In the future, you can test yourself in a small test bed and see what the error is in your favorite javascript debugger:

http://jsfiddle.net/jfriend00/FcSKR/

var jsonString = '{"status":"OK","addresses":[0,1,2,3,4,5]}';
var jsonObj = eval("(" + jsonString + ")");
alert("success");

If you still get an error with {"status":"OK","addresses":[0,1,2,3,4,5]} and the adding of parens before sending to eval, then your data isn't what you think it is and you need to do some debugging to see exactly what is in the response (look at the value in the debugger, put the value into an alert, etc...). There is probably some other stuff in the response that you didn't know would be there.

Note: there are some situations where a JSON parser like JSON.parse() and a legal JSON string is safer than eval() with Javascript that can be anything.