Checking if Storage is supported

[csdude55]

I'm currently using this to either show the result of sessionStorage, or if typeof(Storage) is undefined then it tries a function that reads a cookie, and as a last resort it return false.

Like so:

var saveName = 'blahblahblah';

getObj = JSON.parse(
 typeof(Storage) !== 'undefined' ?
  sessionStorage.getItem(saveName) || false :
  getCookie(saveName) || false
);

(where getCookie() is a function defined separately, and not really relevant to this thread)

I'm not able to test on older browsers, but am I right that this would work just as well?

var saveName = 'blahblahblah';

getObj = JSON.parse(
 window.sessionStorage.getItem(saveName) ||
 getCookie(saveName) ||
 false
);

[ronin]

One way to check if sessionStorage is supported would be to run:

Object.keys(window).indexOf('localStorage') > -1;

This will return true if there is support and false if not.

[ronin]

Probably a more verbose explanation would be helpful.

Essentially, the browser's global window object has a lot of entries - and many of these conveniently indicate (simply by being present) that the browser supports that particular feature.

Because of this you can usually query:

if (Object.keys(window).indexOf('myFeature') > -1) { [...] }

or, more concisely:

if ('myFeature' in window) { [...] }

and that will reveal browser support.

[ronin]

In much the same vein, if you want to see a full list of global window object entries, simply run:

console.log(window)