How to store objects in HTML5 localStorage

Question

However, it appears that my object is being changed to a string when I try to store a JavaScript object in HTML5 localStorage.

Using localStorage, I can save and get primitive JavaScript types and arrays, but objects don't appear to function. Must they?

var testObject = { 'one': 1, 'two': 2, 'three': 3 };
console.log('typeof testObject: ' + typeof testObject);
console.log('testObject properties:');
for (var prop in testObject) {
    console.log('  ' + prop + ': ' + testObject[prop]);
}

// Put the object into storage
localStorage.setItem('testObject', testObject);

// Retrieve the object from storage
var retrievedObject = localStorage.getItem('testObject');

console.log('typeof retrievedObject: ' + typeof retrievedObject);
console.log('Value of retrievedObject: ' + retrievedObject);

typeof testObject: object
testObject properties:
  one: 1
  two: 2
  three: 3
typeof retrievedObject: string
Value of retrievedObject: [object Object]

It appears to me that the input is converted to a string before being stored by the setItem method.

This behavior is present in Safari, Chrome, and Firefox, thus I infer that it is not a defect or restriction unique to any one browser but rather my misinterpretation of the HTML5 Web Storage definition.

I have made an effort to understand the structured clone algorithm that is mentioned in 2 Common infrastructure. I'm not sure what it's saying exactly, but perhaps my issue has to do with the fact that the properties of my object aren't enumerable (???).

Is there a simple solution?