Question

I’ve worked with localStorage across multiple windows before without any problems, but for some reason in this new application it is not working at all.

I have two pages, PageA and PageB. PageA sets some data in localStorage like so:

var someData = {
    item1: 'foo',
    item2: 'bar'
};
window.localStorage.setItem('someKey', JSON.stringify(someData));

If I immediately try to read the data via JSON.parse(window.localStorage.getItem('someKey'));, it works fine.

PageA then calls a window.open(PageBURL) to open PageB. In PageB, when I attempt to read the value from localStorage, all I get is null:

JSON.parse(window.localStorage.getItem('someKey')); // gives me null

Both pages have identical document.domain values. There must be something stupid I am missing, does anyone have any ideas of things to double check?

Answer 1

Turns out localStorage runs under the full host domain, not the javascript document.domain.

PageA runs under "foo.common.net" with a document.domain of "common.net".

PageB runs under "bar.common.net" with a document.domain of "common.net".

If I switch PageA to run under "bar.common.net", I am able to read the data without a problem.