Chrome storage API not working with content script

Question

I'm using chrome storage API to save data that needs to be accessed on content script page. When I load data in extension settings page like this

document.write("chrome.storage.sync.get(\"password\", function(items) {\n");
document.write("var true_password = items.password;\n");
document.write("});\n");

it works, but the same code doesn't work with content script...

I'm getting this error

Uncaught TypeError: Cannot read property 'sync' of undefined

Any idea why?

EDIT

manifest.json
{
"name":"app",
"description":"app...",
"version":"0.1",
"manifest_version":2,
"options_page": "options.html",
"permissions": [ "storage" ],

"content_scripts": [
    {
      "matches": ["https://www.my_page.com/*"],
      "js": ["lock.js"]
    }
  ]
}

Check http://stackoverflow.com/questions/17998123/chrome-storage-sync-undefined — Xan, Mar 30 '15 at 23:56
Is the code actually in your `lock.js`, or are you trying it from the console? — Xan, Mar 31 '15 at 00:00
And you reloaded both the extension _and the page you're working with_ after adding the permission? — Xan, Mar 31 '15 at 00:01
So? Did you reload the extension, then the page to refresh the script? Also, double-check your code for typos. This would appear if you misspelled `storage`. — Xan, Mar 31 '15 at 00:03
Yes, I reloaded the extension, and there are no typos because the same code works in setting.html/.js — opengl, Mar 31 '15 at 00:04
Does it matter that I'm writing the code with `document.write("chrome.storage.sync.get(\"password\", function(items) {\n");` in lock.js — opengl, Mar 31 '15 at 00:08
_Of course_, since that code leaves the content script context and executes in the page context, which does not have access to the API. Why are you doing this? — Xan, Mar 31 '15 at 00:09
Maybe, but that makes your question unhelpful. You should edit to include that relevant information. — Xan, Mar 31 '15 at 00:11
There's still the question of why are you using `document.write`. It shouldn't be necessary. — Teepeemm, Apr 01 '15 at 03:35
Because I need to write new html page when user visits xy.com page, and to write html with js I use `document.write` — opengl, Apr 01 '15 at 18:01

score 3 · Accepted Answer · edited May 23 '17 at 12:16

3

Anything you write directly to the page's DOM, be it with document.write or inserting a <script> element, is no longer considered to be a content script.

Instead, it executes outside of the "isolated world" in the page's own context. That means it has no access to content script APIs or variables/functions defined in your content script.

You can still communicate with page-level code, though.

edited May 23 '17 at 12:16

Community

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answered Mar 31 '15 at 00:16

Xan

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Maybe this is a new update "Your extension's content scripts can directly access user data without the need for a background page.": https://developer.chrome.com/extensions/storage – alayli Jun 24 '15 at 02:15
@alayli No. What is meant is accessing extension data (options, etc.) without messaging. – Xan Jun 24 '15 at 07:38

Chrome storage API not working with content script

1 Answers1