accessing json data from jquery

Your JSON-data looks like this:

[
    {
        "k": "label0",
        "v": 0.5
    },
    {
        "k": "label1",
        "v": 99.43
    },
    {
        "k": "label2",
        "v": 2.46
    },
    {
        "k": "label3",
        "v": 46.29
    },
    {
        "status": "OK"
    }
]

You would have to read your status using

json[4].status

with the 4 as a magical number or length-1 - not desirable. I would consider modifying your servers response to something more useful like this:

{
    "status": "OK",
    "entries": [ ... ] // add your data here
}

In your success callback try:

var parsed = $.parseJSON(data);
$.each(parsed, function (i, jsondata) {
    alert( jsondata.k );
    alert( jsondata.v );
});

To access that status value you would need:

data[4].status

This is because it is an object stored in the the fifth element in an array, with status being a property on the object.

You don't need the eval("("+data+")");. jQuery is automatically parsing the JSON response for you because you specified dataType:'json'

From the jQuery docs for dataType:

"json": Evaluates the response as JSON and returns a JavaScript object. In jQuery 1.4 the JSON data is parsed in a strict manner; any malformed JSON is rejected and a parse error is thrown. (See json.org for more information on proper JSON formatting.)