How do I handle newlines in JSON?

I guess this is what you want:

var data = '{"count" : 1, "stack" : "sometext\\n\\n"}';

(You need to escape the "\" in your string (turning it into a double-"\"), otherwise it will become a newline in the JSON source, not the JSON data.)

You will need to have a function which replaces \n to \\n in case data is not a string literal.

function jsonEscape(str)  {
    return str.replace(/\n/g, "\\\\n").replace(/\r/g, "\\\\r").replace(/\t/g, "\\\\t");
}

var data = '{"count" : 1, "stack" : "sometext\n\n"}';
var dataObj = JSON.parse(jsonEscape(data));

Resulting dataObj will be

Object {count: 1, stack: "sometext\n\n"}

According to the specification, http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf:

A string is a sequence of Unicode code points wrapped with quotation marks (U+0022). All characters may be placed within the quotation marks except for the characters that must be escaped: quotation mark (U+0022), reverse solidus (U+005C), and the control characters U+0000 to U+001F. There are two-character escape sequence representations of some characters.

So you can't pass 0x0A or 0x0C codes directly. It is forbidden! The specification suggests to use escape sequences for some well-defined codes from U+0000 to U+001F:

• \f represents the form feed character (U+000C).
• \n represents the line feed character (U+000A).

As most of programming languages uses \ for quoting, you should escape the escape syntax (double-escape - once for language/platform, once for JSON itself):

jsonStr = "{ \"name\": \"Multi\\nline.\" }";