Check if browser supports localStorage

[MyXoToD]

very very very important!

[MyXoToD]

Looks like there's no reliable method out there. Need more research.

[KevinGimbel]

You can check for localStorage with a one-liner like

var hasLocalStorage = !!(window.localStorage);

The !! turns whatever window.localStorage returns into a boolean, kind of like (bool) $myVar in PHP.

This should work in most cases, anyway you may want to check if localStorage is native or not, so the whole script might look like this:

var hasLocalStorage = (function(window, document, undefined) {
  var hasStorage = window.localStorage;
  var isNative;
  // when there's nothing assigned to window.localStorage
  // return false because there's no localStorage
  if(!hasStorage) {
    return false;
  }

  // This code only gets executed when the above is true, so localStorage is supported
  // Native window.localStorage returns "[object Storage]" when toString() is used
  // the indexOf('[object Storage]') > -1 returns true if "[object Storage]" is found and
  // false if not. 
  isNative = window.localStorage.toString().indexOf('[object Storage]') > -1;
  if(isNative) {
    return true;
  } else {
    // handle non-native implementation? Maybe return -1 or whatever.
   return -1;
  }
}(window, document));

// Example

if(hasLocalStorage > -1) {
 // SUPPORTED \o/
} else {
 window.localStorage = function() { ... }
}

http://codepen.io/kevingimbel/pen/OyVyQW/