How to tell which JSON object is being used (Crockford's or another)?

Question

I'm using Crockford's json2.js. When I want to stringify, I do JSON.stringify()...works great.

However, those who've taken a look at the code know that it defers to existing JSON objects and properties. I suspect a certain problem I'm having may be due to this deference.

Is there a property of the JSON object I can check to see if the browser is using Crockford's object, or some other? It would be nice to be able to do something like alert(JSON.version());

Answer 1

You can decide one to use like this:

<script>window.JSON || document.write('<script src="js/json2.js"><\/script>')</script>

This checks for window.JSON (supported by browser) first if it exists, use that else imports json2.js of Crockford.

update

var whichJSON = null;

if (! window.JSON) {
  document.write('<script src="js/json2.js"><\/script>');
  whichJSON = 'Crockford Version';
}
else {
  whichJSON = 'Browser Native Version';
}

alert(whichJSON);

Answer 2

Before you load Crockford's script, you can check for the global JSON object exactly like he does:

<script>
    var JSON,
        nativeJSON = true;

    if (!JSON) {
        var nativeJSON = false;
        document.write('<script src="js/json2.js"><\/script>');
    }

    if (!nativeJSON) {
        // All JSON objects are using Crockford's implementation
    } else {
        // All JSON objects from here on out are NOT using Crockford's implementation
    }
</script>