a lot of hacking and referencing the PHP tutorials and I got it! here is the answer for anyone else having trouble:
function renewToken(clientID, secret, accessToken) {
var facebookURL = "https://graph.facebook.com/oauth/access_token?client_id=" + clientID + "&client_secret=" + secret +"&grant_type=fb_exchange_token&fb_exchange_token=" + accessToken;
WinJS.xhr({
type: "GET",
url: facebookURL,
}).then(callbackToken, callbackTokenAuthError);
}
function callbackToken(result) {
var url = result.responseText;
var param1 = url.split("&");
var param2 = param1[0].split("=");
localSettings.values["Facebook.AccessToken"] = param2[1];
}
function callbackTokenAuthError(result) {
console.log("no token");
}
just pass your app clientID, secret, and the current expired access token into this function. the new access token is
param2[1];
in my case I save it to local settings.
Hope this helps some people that get stuck!