json values to string array in javascript

Iterate the keys and push the values:

var stringarray = [];
for (var key in data) {
    stringarray.push(data[key]);
}

Use a for-loop to go through the object attributes

var obj = {"prop1":"hello","prop2":"world!"};
var array = [];
for(var key in obj){
    array.push(obj[key]);
}

A "modern" approach worth learning, is, after you've parsed the JSON into a JS object:

Object.keys(obj).map(function(k) { return obj[k]; });

What's going on here? First, we use Object.keys to create an array of all the keys in the object, so ['prop1', 'prop2']. Then we use the handy map function on arrays to transform each of the elements of that array based on a function we give it, which in this case is to retrieve the value for that key from the object.

We could bundle this into a handy little function as follows:

function objectValues(obj) {
    return Object.keys(obj).map(function(k) { return obj[k]; });
}

Believe it or not, there is no such thing built into JavaScript, although the Underscore library has _.values.

Then you could do something as simple as

objectValues(JSON.parse(json))