Question

var jsn=getAttr(ref,"json-data").toString();
console.log(jsn); //{test: true,stringtest:"hallo"}. it's OK.
JSON.parse(jsn); //Uncaught SyntaxError: Unexpected token s, line: line with JSON.parse;

I think JSON.parse does something not right with this data.. I tried to remove stringtest:"hallo" – no result… PS: also I think that I do something wrong then I have asked this question

At the first time I tried JSON.parse("{"+jsn+"}");.

Answer 1

Your JSON is not properly formatted, as your object keys must be surrounded by quotation marks. The following will work:

var jsn = '{"test": true, "stringtest": "hallo"}';
JSON.parse(jsn);

Edit: The RFC4627, which specifies JSON format, states:

2.2. Objects

An object structure is represented as a pair of curly brackets
surrounding zero or more name/value pairs (or members). A name is a
string. A single colon comes after each name, separating the name
from the value. A single comma separates a value from a following
name. The names within an object SHOULD be unique.

  object = begin-object [ member *( value-separator member ) ]
  end-object

  member = string name-separator value

As you can see, JSON objects are composed of name/value pairs, where a name is a string. Again, the RFC says:

The representation of strings is similar to conventions used in the C
family of programming languages. A string begins and ends with
quotation marks. All Unicode characters may be placed within the
quotation marks except for the characters that must be escaped:
quotation mark, reverse solidus, and the control characters (U+0000
through U+001F).

string = quotation-mark *char quotation-mark

quotation-mark = %x22 ; “

So, according to the RFC, keys must be surrounded by double quotes, not single one. Still, I guess some parsers may be more tolerant and accept both of them, but I’d stick to the standard.